Prefixes

Q: What is a prefix?

A prefix is a single letter or a group of letters placed before a root or base word in order to modify its meaning. Prefixes can indicate for example, negation (un-, dis-, mis-), repetition (re-), time or location (post-), or quantity (semi-).

Q: never change a word's class

d's class: Unlike suffixes (which often turn verbs into nouns, like govern to government), prefixes only change the meaning, not the part of speech. A prefixed verb stays a verb, like in replay, and a prefixed adjective stays an adjective, like in unhappy.

Q: variants

fixes have variants: the last letter of the prefix sometimes changes to match the root word’s first letter for easier pronunciation. For example, in- can change to im-, il-, or ir-.

What is a prefix?
A prefix is a single letter or a group of letters placed before a root or base word in order to modify its meaning.
Prefixes can indicate for example, negation (un-, dis-, mis-), repetition (re-), time or location (post-), or quantity (semi-).

When adding a prefix to a word, with very few exceptions, you do not need to alter the spelling of the base word; simply attach the prefix to the beginning. There are a few exceptions: the base word sequel loses its first two letters when combined with prefixes such as pre- or inter-, creating the words prequel — a story that precedes another story — and interquel — a story that takes place between two other stories.
With some prefixes, like co- and non-, you might need to add a hyphen (-) to improve readability or separate vowels. Always use a hyphen before proper nouns, such as un-American or pro-European.

Keep in mind that when a prefix ends with the same letter the root word begins with, both letters must be kept, as seen in misspell (mis+spell) or unnamed (un+named).

Prefixes never change a word's class: Unlike suffixes (which often turn verbs into nouns, like govern to government), prefixes only change the meaning, not the part of speech. A prefixed verb stays a verb, like in replay, and a prefixed adjective stays an adjective, like in unhappy.

Some prefixes have variants: the last letter of the prefix sometimes changes to match the root word’s first letter for easier pronunciation. For example, in- can change to im-, il-, or ir-.

Which prefix should you use for negation?
There is no an exact rule for choosing a prefix for negation. The best way to learn them is through practice and memorization.

Can I add different prefix to the same base word?
Sometimes, yes, but the meaning of the word will change depending on the prefix.
For example, you can add in-(not) (which becomes im-) and un- to the word measurable, but they carry slightly different connotations. While both immeasurable and unmeasurable mean incapable of being measured, they are used in different contexts. Immeasurable means that something cannot be measured because of its very nature—it is too vast, immense, or extreme to be quantified. On the other hand, unmeasurable usually means that there is a physical or technical barrier to measuring it, such as a lack of proper tools.
Another example is unlike and dislike which have very distinct meanings. Unlike means that something differs from something else, whereas dislike means to have a negative feeling toward something.

Be careful: some words look like they have a prefix but actually do not, such as uncle or country. In many cases, if you remove the prefix and the remainder is a real English word (like type in mistype), it is a true prefix.
However, keep in mind that some roots derived from Latin or Greek cannot stand alone as independent English words but still function with prefixes, such as supersonic or supervise.

Prefix List

anti-

Origin: Greek

Meaning: against, opposite, prevent

Examples:

antihero (main character without heroism)
antibiotic (medicine that fights bacteria)
anticlockwise (turning left around a clock)
antisocial (avoids other people, not friendly)
antivirus (software blocking computer viruses)
antiserum (serum with antibodies)
antiseptic (substance that stops infection)
antiracism (opposition to racial discrimination)
antioxidants (substance that stops rusting)
antihistamine (medicine reducing allergic reactions)
antibody (blood protein that fights germs)
anti-bullying (preventing hurtful actions)
antiallergen (substance preventing allergies)
antithesis (a contrasting idea)
antifreeze (liquid that prevens freezing)
antimagnetic (resistant to magnetism)
anti-static (preventing static electricity)
antigravity (force that resists gravity)
anti-government (opposed to the government)
antimicrobial (destroys or stops harmful microorganisms)
antiparallel (move in opposite directions)
anticyclone (high-pressure weather system)

Words with foreign roots

Some words begin with the same letters as the prefix, but they come from another (mostly Latin) language and the prefix and the root word stuck together for a long time. To check, remove the prefix and see if the remaining part is a foreign root word.

Examples:

antigen (substance triggering immune response)
antipathy (strong feeling of dislike)
antidote (substance that counteracts poison)

Exceptions

Although words start with the same letters as the prefix, they do not actually contain the prefix. To check, remove the prefix and see if the rest of the word is a real word or a foreign root.

antique (old and valuable item)
anticipate (expect or prepare for something to happen)

auto-

Origin: Greek

Meaning: self, own, by itself

Examples:

autobiography (a life story written by oneself)
autocorrect (automatic spelling correction)
autofocus (having the ability to focus automatically)
autograph (a person's signature)
autoimmune (immune system attacking itself)
autoload (load without user input)
automobile (a car)
autopilot (automatic flying control)
autofill (fills in information automatically)
auto-restart (restarts by itself)
auto-reply (respond automatically)
automotive (related to motor vehicles)

Words with foreign roots

Examples:

automatic (operates on its own)
autonomy (independence to make decisions)
autocrat (a ruler with total power)
autodidact (self-taught person)
automorphic (changing and producing itself)

co-

Origin: Latin

Meaning: with, together, secondary, completely

Examples:

co- (before vovels, h, gn, w, s and sometimes c)

cooperate (work together willingly)
coordinate (help work together smoothly)
coexist (live together peacefully)
cohabitation (share living space)
co-author (write or create together)
co-found (establish together)
co-worker (someone who works with you)
co-finance (fund together)
co-administration (using two treatments together)
co-pilot (a person assisting the captain during flight)
co-own (share ownership with others)
co-founder (person who starts a company with others)
co-production (work created by multiple companies)
co-defendant (another person in the same jury case)
co-equal (having the same rank, status, or importance)
cosponsor (a joint financial supporter)
co-host (a partner to the main host)

com- (before b, m, p)

compress (squeeze together)

cor- (before r)

correspond (communicate through writing)
correspond (match, fit, be similar, or agree fully)

co-organise (plan jointly)

Words with foreign roots

Examples:

co- (before vovels, h, gn, w, s and sometimes c)

co-opt (choose someone to join a group)
cognition (mental process of understanding)
cognitive (related to thinking skills)
coincidence (occurring at the same time unexpectedly)
cohesion (the act of things joining together)

con- (before most consonants)

connect (join things together)
construct (put together parts to make)
contribute (help achieve something together)
conform (follow shared rules)
converge (meet at one point)
consolidate (combine for strength or effectiveness)
confer (discuss together)
conspire (planning or committing a crime together)
congregate (gather as a group)
concoction (a strange mix of various things)
convince (persuade, make someone believe that something is true)
constellation (group of stars that form a pattern)

col- (before l)

collide (crash into each other)
collect (bring or gather things together)
collaborate (work together on purpose)
collapse (fall down suddenly)
collocation (words that often go together)
collusion (secret agreement or cooperation between groups)

com- (before b, m, p)

combine (join into one)
compare (look at similarities and differences)
company (a business or organisation)
compete (try to win against others)
compose (creating art; from various things)
companion (a friend who is with you)
component (a part of something larger)
compile (gether thing together and arrange them)
commemorate (honour a memory together)

cor- (before r)

correlate (connect different things)
corroborate (support a story with evidence)
corrode (gradually wears away; became rusty)

Exceptions

Although words start with the same letters as the prefix, they do not actually contain the prefix. To check, remove the prefix and see if the rest of the word is a real word or a foreign root.

co- (before vovels, h, gn, w, s and sometimes c)

coin (a piece of metal money)
cotton (soft thread made from a plant)
country (an area with set borders)
court (area for sports games)
courage (bravery in facing challenges)
coast (land beside the sea)
coffee (dark drink that energizes you)

con- (before most consonants)

control (manage activities, supervise)
continue (go on doing something)
continent (large land mass)

com- (before b, m, p)

comb (a toothed tool used to untangle and style hair)
compost (decomposed organic matter for soil)

corridor (a passage connecting rooms)
conga (South American line dance; a tall and narrow drum)

dis-

Origin: Latin

Meaning: not, opposite, remove, or separate

Examples:

disappoint (to let someone down)
disagree (have different opinion)
disobey (ignore rules or orders)
disappear (no longer seen, become invisible)
disable (make unable to work or change)
disconnect (separate or detach something)
disuse (no longer in use)
dislike (have a negative feeling about)
dishonest (not telling the truth)
disobedient (not following instructions)
disability (condition that limits abilities)
disadvantage (a condition that makes life harder)
distrust (doubt based on past experience)
disrespect (impolite or rude treatment of others)
dissimilar (not alike; different)
disallow (refuse or not permit something)
disapprove (believe that something is wrong)
disqualify (prevent or stop from participating)
disinfect (kill germs by cleaning)
discourage (make someone feel less confident)
disorder (abnormal condition; state of chaos)
discomfort (unpleasant physical feeling)
discontinue (terminate or stop an activity)
disloyal (unfaithful; breaks trust or promises)
disorganised (lacking order or structure)
dissatisfied (not happy with a result)
disguise (hide one’s true identity)
disassemble (take something apart)
distasteful (disgusting or unpleasant)
disintegration (breaking apart into small pieces)
dismount (get off a vehicle or horse)
disposable (meant to be thrown away after using)
disquiet (feeling worried or uneasy)

Words with foreign roots

Examples:

distribute (share out to others)
distract (take attention away)

Exceptions

Although words start with the same letters as the prefix, they do not actually contain the prefix. To check, remove the prefix and see if the rest of the word is a real word or a foreign root.

disaster (a catastrophic event)
disease (a sickness affecting the body)
discuss (to talk about a topic together)

in- (into)

Origin: Latin

Meaning: into, in, on or upon

Examples:

im- (before b, m, p)

imprison (putting someone in jail)
immigrate (move to another country to live there)
implant (device placed in the body)
impress (surprise or amaze someone)

inside (the inner part of something)
indoor (inside a building)
ingrown (growing beneath the skin)
inland (away from the coast and sea)
income (money someone earns)
infusion (soaking plant material in liquid)
input (data entered into a system)
insight (understanding of something)
imprint (press a mark onto something)
incorporate (to blend into a whole)

Words with foreign roots

Examples:

im- (before b, m, p)

import (carry or bring goods into the country)
immerse (deeply involved in an activity)

innovation (new idea or method)
inspire (encourage someone to act)
incarnation (soul's manifestation in a body)
invasive (treatment with entering the body)
invasive (non-native species that harms)

Exceptions

Although words start with the same letters as the prefix, they do not actually contain the prefix. To check, remove the prefix and see if the rest of the word is a real word or a foreign root.

industry (business or manufacturing sector)
injury (body harm or damage)
invite (request someone's presence)
instrument (tool for tasks or music)
innocent (not guilty or inexperienced)
insect (a six-legged animal with three body parts)

in- (not)

Origin: Latin

Meaning: not, the opposite of

Examples:

im- (before b, m, p)

immature (not fully developed; behaving like a child)
immoral (against accepted moral standards)
impossible (not able to happen)
impatient (not able to wait calmly)
imperfect (demaged, having flaws or mistakes)
impolite (rude and disrespectful)
immortal (lives forever and never dies)
improper (not suitable, correct, or lawful)
immobile (unable to move)
immeasurable (too large to measure)
immaculate (perfectly clean or neat)
impractical (not useful in real life)
imprecise (not exact, inaccurate)
impure (not clean; mixed with other things)
imbalance (uneven distribution or stability)

il- (before l)

illegal (not allowed or permitted by law)
illegible (difficult to read)
illogical (not reasonable or sensible)
illiberal (not open to new ideas)
illiterate (unable to read or write; not educated)

ir- (before r)

irregular (not normal or typical; odd)
irrelevant (not related to the topic)
irresponsible (not showing proper care or concern)
irremovable (cannot be separate or taken away)
irreversible (cannot return to original state)
irreplaceable (unable to be substituted by anything else)
irrational (not logical or based on reason)
irrevocable (cannot be reversed, or taken back)
irrefutable (cannot be proven false)

inactive (not participating in any actions)
incorrect (wrong or not right)
indirect (not straightforward or the simplest way)
invisible (cannot be seen or observed)
incomplete (not fully finished)
inaccurate (not exact or precise)
inexpensive (cheap, low-priced)
infamous (well-known for bad actions)
inappropriate (not right for the situation)
invalid (not acceptable or correct)
intolerant (not accepting differences)
insensitive (not aware of feelings or pain)
insufficient (not enough, inadequate)
insignificant (not important or noticeable)
informal (casual and unofficial)
inadequate (below the standard; insufficient)
inaudible (unable to be heard)
incompatible (not able to fit or work together)
inedible (not fit for eating)
inefficient (not using time or resources well)
inflexible (unable to bend or change)
inexpert (lacking experience or skill)
insecure (lacking safety or confidence)
inconsistent (changes its quality too often)
inanimate (not alive, lacking life)
indifferent (having no preference)
impersonal (without personal feelings)
interminable (seemingly endless)
inevitable (unavoidable, certain to happen)
infrequently (occasionally, not happening often)
inexhaustible (never runs out or gets tired)
independent (not relying on others)
impenetrable (unable to be seen or passed through)
indispensable (absolutely necessary)
infinite (endless or limitless in size)
insoluble (unable to dissolve in liquid)
indistinguishable (too similar to tell apart)
inconvenient (causing trouble or discomfort)
indescribable (too extraordinary to put into words)

Words with foreign roots

Examples:

insomnia (unable to sleep)
indefatigable (never tired, tough)

Exceptions

Although words start with the same letters as the prefix, they do not actually contain the prefix. To check, remove the prefix and see if the rest of the word is a real word or a foreign root.

im- (before b, m, p)

immune (resistant or protected from illness)

il- (before l)

illness (condition of being sick)

ir- (before r)

irrigate (give water to plants or land)

industry (business or manufacturing sector)
injury (body harm or damage)
invite (ask someone to join)
instrument (tool for tasks or music)
innocent (not guilty or inexperienced)
insect (a small, six-legged creature)

inter-

Origin: Latin

Meaning: between, among

Examples:

interurban (between cities or towns)
intercity (between major cities)
international (involving more than one country)
interrelated (things that influence each other)
interactive (involves users working together)
internet (global computer network)
interact (work together or influence)
interaction (two-way communication or cooperation between people)
interchange (exchange or share with one another)
interconnect (link things together)
intergalactic (between galaxies)
intermediate (between stages)
intercontinental (between continents; global)
interpersonal (between people)
interface (connection point for systems)
intertwine (twist or wind together)
interlock (connect securely)
intercellular (between cells)
interplanetary (between planets)
intermolecular (Between molecules)
intertitle (text between film scenes)
interdependent (relying on each other)

Words with foreign roots

Examples:

intercept (to stop something from reaching its target)
interrupt (pause something for a moment)
interregnum (time between two rulers)

Exceptions

Although words start with the same letters as the prefix, they do not actually contain the prefix. To check, remove the prefix and see if the rest of the word is a real word or a foreign root.

intern (supervised work experience)
interior (the inside part of something)

macro-

Origin: Greek

Meaning: large, long

Examples:

macroeconomics (study of large-scale economies)
macrotrend (llarge-scale, long-term changes)
macrostructural (large-scale, overall structure)
macroanalysis (large-scale examination)
macroscale (very large size range)
macroenvironment (big external factors influencing something)
macronutrient (essential nutrients your body needs)
macromolecule (a large molecule)

Words with foreign roots

Examples:

macrocosm (a large system or universe)
macrocyte (a large red blood cell)
macrophage (large white blood cell that fights germs)

micro-

Origin: Greek

Meaning: small, low in quantity

Examples:

microwave (short electromagnetic waves used for cooking)
microchip (tiny electronic circuit)
microbus (small passenger vehicle)
microscale (extremely small size)
microplastic (tiny plastic particles)
microclimate (local weather conditions)
microeconomics (study of small markets)
microtransaction (small online purchase)
microstructure (small-scale internal structure)
microanalysis (careful study of tiny details)
microprocess (small-scale procedure)
microhabitat (small living environment)
microdose (very small amount of medicine)
microbiologist (scientist studying microbes)
microbiology (study of microbes)
microcomputer (small personal computer)
microfilm (photographical film that stores documents)
microcontroller (small programmable computer chip)
microorganism (very small living organism)
microsurgery (surgery using tiny instruments)
microcircuit (tiny electronic circuit)
microsensor (very small sensing device)
microbiome (community of microbes)
microworld (small, specific environment)
microelectronics (technology using tiny electonic components)
microstate (very small country)
microdomain (a tiny section of a bigger system)
micrometeorite (tiny space rock)
micrograph (image made with a microscope)
microgravity (very low gravity condition)

Words with foreign roots

Examples:

microphone (sound converter device)
microscope (device for seeing very tiny objects)
microbe (tiny living organism)

mis-

Origin: Greek

Meaning: wrong, incorrect, or badly done

Examples:

misbehave (act badly)
mislead (give false information to someone)
misspell (spell a word incorrectly)
misadvise (give a bad, incorrect, or unhelpful advice)
mismatch (not fit together properly)
misread (read or understand wrongly)
mistype (type incorrectly by accident)
misconception (false belief about something)
miscolour (to give a wrong colour to something)
miscalculate (compute a result incorrectly)
misjudge (form a wrong opinion)
misuse (use in the wrong way)
mistrust (doubt based on feelings)
misunderstand (to interpret incorrectly)
misinform (provide incorrect information)
misinterpret (to understand incorrectly, misunderstand)
misdiagnose (wrongly identify a condition)
mishear (hear something incorrectly)
misplace (put in the wrong spot)
misrepresent (describe incorrectly)
misidentify (identify wrongly or incorrectly)
misprint (printing mistake)
miscommunicate (share information incorrectly)
mispronounce (say a word incorrectly)
misdirected (sent to the wrong place, often on purpose)
misguide (lead someone the wrong way, often by mistake)
misfortune (unpleasant event or circumstance)

Exceptions

Although words start with the same letters as the prefix, they do not actually contain the prefix. To check, remove the prefix and see if the rest of the word is a real word or a foreign root.

mist (a thin, light fog)
mission (a specific task to complete)
miserable (feeling very unhappy or uncomfortable)
mischief (playful trouble-making)

multi-

Origin: Latin

Meaning: many

Examples:

multipurpose (useful for various tasks)
multicultural (involving many cultures)
multimedia (combines text, sound, images, and videos)
multinational (company operating in several countries)
multifocal (having multiple focal points)
multicellular (organism with many cells)
multicoloured (having different colours at once)
multimillionaire (a person with a lot of money)
multitask (perform several tasks at once)
multiplayer (many people playing together)
multivitamin (contains many vitamins)
multichannel (many ways to communicate)
multisensory (involving several senses)
multisport (involving several sports)
multifunctional (serves many purposes)
multithreaded (handles multiple tasks at once)
multidisciplinary (involving many subjects of study)
multivalent (has many meanings or values)
multimodal (uses different methods or forms)
multigenerational (involves several generations)
multistorey (having several floors)
multitiered (having several layers)
multiprocessor (has several processors working together)
multidimensional (having many sides, aspects or layers)
multimeter (tool for measuring electricity)

Words with foreign roots

Examples:

multilateral (involving many groups)
multilingual (speaks many languages)
multiplex (many functions together)
multifarious (very varied or diverse)

non-

Origin: Latin

Meaning: not

Examples:

non-academic (not related to school subjects)
non-existent (not real or present)
non-fiction (writing about real events or facts)
nonlinear (not in a straight line)
non-smoker (person who does not smoke)
non-stick (surface food does not stick to)
non-stop (without pause or interruption)
non-urgent (not needing immediate attention)
non-adaptive (not adjusting to environmental changes)
non-aggressive (not angry or violent)
non-biological (not made from living things)
noncommittal (not expressing a firm opinion)
non-profit (not intended to make profit)
nonsense (silly or foolish idea or word)
non-standard (not typical or usual)
non-toxic (safe and not poisonous)
nonverbal (without spoken words)
non-fat (without any fat)
non-violent (not using physical force)
non-binary (not limited to two genders)
non-member (not part of a group)
non-essential (not necessary; not strictly needed)
non-resident (not living in a place)
non-renewable (cannot be used again or replaced)
non-fictional (based on real events or facts)
non-compliance (not following rules)
non-traditional (done in a new, different way)
non-negotiable (cannot be altered)
nonreturnable (cannot be sent back)
non-conformist (someone who rejects norms or trends)
non-intervention (not getting involved)
non-viable (unable to live, grow, survive, or succeed)
non-trivial (not obvious, not easy to solve)
non-sequential (not following a set order)
non-zero (not equal to zero)
non-living (not alive or was never alive)
non-English (not related to the English language)
non-American (not from the United States)
non-European (not from Europe)
non-periodic (not happening at regular intervals)
non-invasive (treatment without surgery)
non-functioning (not working)
non-neural (not relating to the nervous system)
non-biodegradable (cannot naturally decompose)
non-native (not originally from that area)

over-

Origin: English

Meaning: too much, above, across, beyond, superior

Examples:

over-abstract (too general and vague)
over-amplified (made excessively loud)
over-conscious (excessively self-aware)
over-control (excessive regulation)
over-obvious (very easy to understand)
overrepresent (shown more than exists)
overact (exaggerated emotional acting)
overambitious (too eager to succeed)
overbalance (tip over and fall)
overbooked (more reservations than place)
overcast (sky covered with clouds)
overcharge (charge excessively)
overcoat (long warm coat)
overcomplicated (unnecessarily complex)
overconfident (confidence beyond ability)
overcooked (apply heat too long)
overcrowded (filled with too many people)
overdirect (to control or instruct too much)
overdo (go beyond what is necessary)
overdose (dangerous drug amount)
overdraft (spending causes bank account deficit)
overdrawn (spent more money than available)
overdress (dress too formally for an occasion)
overdue (not on time, late)
overeat (consume too much food)
overestimate (guess or belive something is larger than it is)
overexcited (excessively emotionally stimulated)
overfeed (give too much food)
overflight (aircraft passing above)
overflow (liquid spills over the edge)
overground (above the ground)
overhang (to extend beyond something below)
overhead (above someone's head)
overheat (make too hot)
overheated (became too hot)
overindulgence (excessive enjoyment or pleasure)
overjoyed (extremely happy)
overland (travelling across land)
overlap (partly cover the same area)
overlay (a covering placed on top)
overload (an excessive amount to manage)
overpay (pay more than necessary)
overprecise (too exact for a purpose)
overpriced (more expensive than worth)
overprotect (to protect someone excessively)
overqualified (having more skills than needed)
overrate (to value too highly)
overrated (more appreciated than deserved)
overreact (respond too strongly)
overruled (reject or turn down a decision using one's authority power)
overseas (in a country across the sea)
oversimplify (make something too basic, with missing details)
oversleep (wake up too late)
overthink (to think about the same thing too much)
overthrow (remove from power)
overtime (hours beyond the usual work schedule)
overturn (reverse or change a decision)
overweight (obese, above the healthy heaviness)
overwork (work excessively)
overlook (a higher place that provides a view)
overlook (ignore, miss something important)
overeducated (having more qualifications than needed)
oversee (supervise or manage something)
overnight (during the entire night)
overfishing (catching too many fish)
overstock (excess goods available)
overgraze (damage land by excessive animal feeding)
overharvesting (removing too many natural resources)
overburden (give too much weight, work, or pressure)
overwater (give excessive water)
overwhelm (make someone feel too much emotion)

post-

Origin: Latin

Meaning: after, behind

Examples:

post-mortem (body examination after death)
postnatal (period after childbirth)
postgraduate (further study after degree)
postscript (extra note after a letter)
post-war (period after World War II)
postmodern (an art style from the late 20th century)
postoperative (period of time after surgery)
postseason (after the sports season ends)
post-industrial (society following the industrial era)
post-traumatic (condition following trauma or distress)
post-apocalyptic (state after a catastrophic event)
postprandial (period after a meal)
postsynaptic (after a signal reaches another nerve cell)
post-nominal (letters after a person's name)
post-production (work after a film is recorded)
postdoctoral (research done after a PhD)
postglacial (after the last ice age)
postcolonial (after foreign rule ends)
postnuptial (period after marriage)
post-dated (dated for a future time)

Words with foreign roots

Examples:

posthumous (happening after one’s death)
postpone (delay until later)
postmeridian (time between noon and midnight)

Exceptions

Although words start with the same letters as the prefix, they do not actually contain the prefix. To check, remove the prefix and see if the rest of the word is a real word or a foreign root.

postal (relating to mail delivery)
poster (printed picture for decoration)
postage (cost of sending mail)
postcard (greeting card sent by mail)
postmark (stamp on the letter or parcel)
posture (position of the body)

pre-

Origin: Latin

Meaning: before, earlier, prior to

Examples:

prearranged (planned and agreed earlier)
pre-existed (existed earlier than something else)
pre-book (reserve in advance)
precaution (step taken to avoid harm or danger)
preconception (an opinion formed without enough information)
precooked (partially cooked in advance)
preface (introduction of a book or speech)
preheat (make hot beforehand)
prehistoric (from before written records)
premature (happening too early)
premixed (combined beforehand)
prepay (pay in advance)
preprint (a document shared before formal publication)
prequel (story set earlier but released later)
presale (selling before release)
preview (view before launch)
pre-recorded (made and edited beforehand)
pre-test (initial test before the main one)
pre-intermediate (before the intermediate level)
pre-designated (chosen or set beforehand)
predetermined (decided or arranged earlier)
pre-portioned (already divided into smaller pieces)

Words with foreign roots

Examples:

precede (come before something)
predecessor (a person who came before another in position)
predict (guess or estimate a future event)
preliminary (occurring before a main event)
precocious (mature for one's age)

Exceptions

Although words start with the same letters as the prefix, they do not actually contain the prefix. To check, remove the prefix and see if the rest of the word is a real word or a foreign root.

predator (animal that preys on others)
pregnant (expecting a baby)
press (to push firmly)
pretty (attractive)
precise (exact, clear, and accurate)
pretzel (twisted baked snack)
prestige (respect due to achievements)
press (written media; newspaper)

pro-

Origin: Latin, Greek

Meaning: forward, before, in favour of

Examples:

semipermeable (material that lets some things pass, but blocks others)
semiweekly (happens twice a week)
semiannual (occurs two times a year)
semiautomatic (partly self-operating)
semi-detached (connected to another house by one wall)
semifinal (round before the final match)
semicircle (half-circle shape)
semisolid (partially solid)
semi-sweet (slightly sweet)
semidry (has little liquid or water)
semi-arid (region with limited rainfall)
semidarkness (having very little light)
semi-permanent (lasts long but can change)
semi-professional (partly professional; part-time activity)
semipublic (partly private and accessible)
semi-rural (partly rural and partly urban)
semi-skilled (partially trained)
semi-structured (partially organised system)
semitransparent (partly see-through)
semi-independent (partly free from control)
semi-autonomous (partly self-governing)
semi-official (having partial authority or permissions)
semiprivate (partially shared with others)
semi-flexible (bends a little without breaking)
semiconductor (material that conducts electricity partially)
semi-coherent (partly understandable, not fully clear)
semi-colon (punctuation mark for connecting ideas)
semi-precious (a valuable but less rare gem)
semi-desert (partly dry region with low rainfall)
semi-enclave (partly enclosed area)

re-

Origin: Latin

Meaning: again, back, backward, against

Examples:

redo (repeat; do again)
refresh (update, make new again)
return (go, put, give, or send back)
reappear (appear again)
redecorate (change the decoration again)
redisplay (show again in public)
respell (spell again)
rebook (reserve or arrange something again)
reread (read again)
retype (type something again)
recall (bring back a memory or remove)
reconnect (join again after separation)
redirect (send in another direction)
reuse (use again instead of throwing away)
rebuild (construct again after damage)
recalculate (perform a calculation again)
recycle (make something usable again)
rearrange (change the order)
recreate (make something again)
redraw (draw something again)
refill (fill something again)
refuel (fill with fuel again)
reheat (make warm again)
remix (change music tracks)
remove (take away, detach)
renew (make new or valid again)
reopen (to open once more)
repay (pay back)
replace (exchange one item for another)
replay (play something again)
restart (resume or start again)
resubmit (send again for review)
retell (tell again)
retry (attempt again)
resend (dispatch or post again)
recharge (restore energy)
reconsider (think about something again)
unscrew (remove a screw)
recount (calculate again or retell a story)
rewind (turn or move backward)
reincarnation (rebirth in a new body)
reunion (join together again)
reinstate (restore to a former position or state)
reconstruction (restore to original form)
reproduce (create a copy or offspring)
relocate (move to another location)
rename (give a new name)
rethink (consider again carefully)
reschedule (arrange for another time)
regrow (grow again after being lost or damaged)
recite (say something from memory)
reassure (calm someone's worries)

Words with foreign roots

Examples:

revocable (can be withdrawn or cancelled)
reluctant (unwilling to do something)
reflect (to send light back)

Exceptions

Although words start with the same letters as the prefix, they do not actually contain the prefix. To check, remove the prefix and see if the rest of the word is a real word or a foreign root.

real (not imagined; actually existing)
reason (explanation for why something happens)
regret (feeling sorry about a past action)
resident (a person living in a place)
resident (a doctor in hospital training)
religion (belief in gods or deities)
read (look at and understand written text)
regular (occurring often and usual)
realm (kingdom; area of activity or interest)
rectangle (four-sided shape with four right angles)
reptile (cold-blooded animal with a spine)

semi-

Origin: Latin

Meaning: half, partly, not fully

Examples:

semipermeable (material that lets some things pass, but blocks others)
semiweekly (happens twice a week)
semiannual (occurs two times a year)
semiautomatic (partly self-operating)
semi-detached (connected to another house by one wall)
semifinal (round before the final match)
semicircle (half-circle shape)
semisolid (partially solid)
semi-sweet (slightly sweet)
semidry (has little liquid or water)
semi-arid (region with limited rainfall)
semidarkness (having very little light)
semi-permanent (lasts long but can change)
semi-professional (partly professional; part-time activity)
semipublic (partly private and accessible)
semi-rural (partly rural and partly urban)
semi-skilled (partially trained)
semi-structured (partially organised system)
semitransparent (partly see-through)
semi-independent (partly free from control)
semi-autonomous (partly self-governing)
semi-official (having partial authority or permissions)
semiprivate (partially shared with others)
semi-flexible (bends a little without breaking)
semiconductor (material that conducts electricity partially)
semi-coherent (partly understandable, not fully clear)
semi-colon (punctuation mark for connecting ideas)
semi-precious (a valuable but less rare gem)
semi-desert (partly dry region with low rainfall)
semi-enclave (partly enclosed area)

sub-

Origin: Latin

Meaning: under, below, less than, smaller, secondary

Examples:

subtitle (text below a title or video)
submarine (underwater vehicle)
subcontinent (large area of land within a continent)
subculture (distinct group within a culture)
subatomic (smaller than an atom)
subdivide (split into smaller parts)
subheading (smaller heading under title)
subset (a smaller group of a set)
subtotal (partial total before final amount)
subtropical (just outside the tropics)
subzero (temperature below freezing)
subtype (a smaller category of something)
submenu (a menu within another menu)
suburban (area located just outside a city or town)
substandard (below the accepted quality)
subclass (a smaller group within a class)
subtopic (related subject within a main topic)
subcategory (a smaller section within a category)
subordinate (lower in rank or importance)
subcompact (a smaller car or object)
subconscious (mind activity beyond awareness)
subsurface (beneath the surface)

Words with foreign roots

Examples:

submerge (sink completely into liquid)
subdue (bring under control)

super-

Origin: Latin

Meaning: very, extreme, above

Examples:

supercomputer (very powerful computer)
superfast (much quicker than normal)
superglue (very quick-drying glue)
superhero (character with special powers)
supermarket (large self-service store)
superman (powerful superhero character)
supermodel (very famous fashion model)
supernova (an exploding star that shines brightly)
superpower (an extraordinary skill or ability)
superstar (a very famous person)
supernatural (paranormal; not explainable by nature)
supersensitive (responds strongly to small changes)
super-rich (extremely wealthy)
super-strong (extremely strong)
superstore (large shop selling many goods)
superconductor (material with zero resistance)
superintendent (person in charge of a building or area)
supermum (an excellent and caring mother)
supercell (intense storm)
superego (internal ethical and moral compass)
superdense (extremely thick or compact)
supernatant (clear liquid above sediment)

Words with foreign roots

Examples:

supersonic (faster than sound waves)
superfluous (more than needed; extra)
supervise (watch over and direct activities)
superluminar (moving quicker than light)

trans-

Origin: Latin

Meaning: across, through

Examples:

transaction (act of buying and selling)
transatlantic (across the Atlantic Ocean)
transform (a big change or modification)
transfusion (transfer blood into body)
transcontinental (across a continent)
transformation (a complete change)
transmutation (completely change form or nature)
transboundary (crossing borders of countries)
transcultural (crossing cultural boundaries)
transhistorical (beyond historical limits)
transfiguration (a spectacular positive change)

Words with foreign roots

Examples:

translucent (lets light pass partially through)
transmute (change into a different form)
transcend (go beyond normal limits)
transfer (move from one place to another)
transition (shift from one state to another)
translate (converts text between different languages)
translator (interpreter)
transmission (transfer of data, energy, or illness)
transmit (send or pass data, energy or illness)
transmitter (device that sends signals or data)
transparent (lets light through)
transplant (move living tissue or plants)
transport (carry goods or people)
transcribe (make or copy a written record of something)
transcendent (beyond ordinary experience)
transpose (swap places)
transposon (a DNA sequence that can move within a genome)
transgression (violating a moral rule or law)

ultra-

Origin: Latin

Meaning: extreme, beyond

Examples:

ultra-conservative (thinking very traditionally)
ultra-quiet (producing almost no sound)
ultrafast (moving very quickly)
ultramarathon (race longer than a marathon)
ultra-modern (very new and advanced, up-to-date)
ultrarapid (happening very quickly)
ultra-smart (extremely intelligent)
ultraviolet (light beyond human vision)
ultrasoft (having very gentle texture)
ultralight (having very little weight)
ultrathin (having very little thickness)
ultraclean (completely free from dirt; spotless)
ultra-strong (extremely powerful or durable)
ultrasmall (exceptionally tiny)
ultracompetitive (extremely focused on winning)
ultra-efficient (very effective with little effort)
ultra-sensitive (responds to small changes)
ultra-practical (extremely useful and sensible)
ultrareliable (extremely dependable and consistent)
ultra-secure (extremely protected or safe)
ultraprecise (highly accurate, exact, and detailed)
ultracomplex (extremely complicated)
ultra-intensive (extremely concentrated)
ultraprocessed (highly processed food products)
ultraconserved (very well preserved over time)
ultra-uniform (extremely consistent or even)

Words with foreign roots

Examples:

ultrasonic (sound above human hearing range)
ultracrepidarian (offering advice without expertise)

un-

Origin: Latin

Meaning: not, the opposite of

Examples:

unhappy (feeling sad)
undo (reverse or cancel an action)
unload (remove things from a container)
unfair (not treating everyone equally)
unlock (open something that is secured)
unclear (difficult to understand, confusing)
unafraid (brave and without fear; not scared)
unavailable (not accessible or usable)
uncommon (rare, unusual)
unexpected (not planned or predicted)
uncomfortable (causing discomfort feeling)
unimportant (not significant or valuable)
unhealthy (bad for your health)
unfriendly (not nice or welcoming)
unlimited (without restrictions or boundaries)
unnecessary (not needed, not essential)
unnoticed (not seen or observed)
unsuitable (not appropriate or right for a purpose)
unattractive (plain, not good-looking)
uninteresting (boring, not fun or exciting)
unknown (not recognised or identified)
unlucky (having bad luck)
unpredictable (impossible to foresee)
unsafe (dangerous, risky)
unreliable (not trustworthy)
unusual (rare, not common or ordianry)
unwell (feeling sick)
unable (not capable of doing)
unlike (different from something else)
unreal (not existing in reality)
unworthy (not deserving value or respect)
unanswered (without a reply or solution)
uncertain (not sure about something)
uneasy (slightly worried or anxious)
unemployed (person without a paid job)
unfamiliar (not known or recognised; strange)
unfinished (not completed or done yet)
unfortunately (sadly, regrettably)
unhelpful (not useful or supportive)
unkind (not nice or friendly)
unnatural (strange, artificial, abnormal)
unrelated (not connected to something else)
unpaid (without payment)
unpleasant (not enjoyable or comfortable)
unprotected (without any protection)
unsolved (not figured out yet)
unstable (not steady or safe)
unwanted (not desired, needed, or wished)
unwelcome (not wanted or invited)
unwrap (take off covering)
unzip (open with a zip or extract)
unsure (not certain or confident, doubtful)
unseen (hidden or not visible)
unpack (take items out of a bag or a box)
untie (unfasten a knot)
unfit (not healthy or suitable)
untidy (disorganised, messy, or dirty)
unattended (not looked after)
unpopular (not favoured or liked by many)
unequal (not the same in any measurement)
unsteady (wobbly or unstable)
unambitious (not wanting to achieve success)
unuseful (having no practical value)
unintentional (occurring accidentally)
unfit (not suitable for a task)
unshaven (having uncut facial hair)
uncultivable (not suitable for growing crops)
unfulfilled (not achieved or satisfied)
unfold (open or spread gradually)
unintended (not planned or expected outcome)
unspoken (not said aloud)
uninhabitable (not suitable for living)
unbothered (not worried or upset)
undisputed (unquestioned, accepted without doubt)
unadaptable (unable to adjust or accommodate)
unimaginable (impossible to visualise)
unfertilised (joined with a male reproductive cell or not given added nutrients)
unwilling (not eager to do something)
unchanging (staying the same over time)
unevenly (not regular or smooth)
unbearable (impossible to endure)
uncontrollable (impossible to restrict or manage)
undoubtedly (certainly, definitely)
unpaired (not matched or not forming a pair)
unexplained (not clear or understandable)
undigested (not processed by digestion)
unusable (not fit for purpose)
undeniable (certainly true)
unrecognised (not identified or accepted)
unprofitable (not making financial profit)
unofficial (not fromally recognised)
unauthorised (not officially permitted)
unaware (lacking knowledge of something)
unavoidable (unable to be prevented or stopped to happen)
unsustainable (cannot be maintained over time)
unsuspecting (not expecting anything unusual)
unintelligent (lacking the ability to think and understand things quickly)
unsuccessful (not achieving the desired goal)
unwashed (not cleaned with water)
unarmed (not carrying weapons)
uncountable (cannot be counted one by one)
untouched (left in original condition)
uneaten (food left without being consumed)
unfaithful (not being loyal)
unsightly (not pleasant to see)
unprecedented (never happened or seen before)
unravel (untangle or solve problems)
undeclared (not formally stated or announced)
unpublished (completed but not released)
uncut (not shortened, trimmed, or divided)
unidentified (unknown, unsourced, or anonymous)
unsurprised (not shocked by an expected event)
unease (feeling of discomfort or worry)

Exceptions

Although words start with the same letters as the prefix, they do not actually contain the prefix. To check, remove the prefix and see if the rest of the word is a real word or a foreign root.

under (beneath something)
undulate (move in wave-like motion)
unit (one complete item or part)

under-

Origin: English

Meaning: not enough, below, incomplete

Examples:

underarm (area below the arm)
undercharge (charge less than necessary)
undercooked (not cooked fully)
undercover (working secretly)
underdeveloped (not fully grown)
underdressed (wearing too casual clothes)
underestimate (think that something is smaller than it is)
underfeed (provide less food than needed)
underprivileged (lacking basic life resources)
underlay (layer placed beneath)
underline (draw a line below)
underpaid (paid less than desired)
underpants (male underwear)
underpass (road below another)
underpay (paying someone less than needed)
underperform (do less well than expected)
underrate (value something less than it is)
underrated (valued less than it deserves)
underrepresent (not having enough of them in a group)
undersell (offer at a lower price)
underwater (beneath water's surface)
underwear (clothes worn beneath outerwear)
underworld (hidden criminal society)
undervalued (seen as less valuable)
underlying (the main reason beneath something)
underfunded (receiving insufficient funds)
undergo (face something difficult)
underworld (the realm of the dead in mythology)