What is a prefix? A prefix is defined as a syllable or group of syllables added to the beginning of a word or a root word stem to alter its meaning. Prefixes add complexity to the English language and make it possible to create new words that are easily understood by speakers everywhere. Reviewing a variety of prefix examples and what they mean will help you apply logic to new words and decode them appropriately.
15 Prefixes That Negate Another Word
Several prefixes serve to make the new word mean the opposite, or nearly the opposite, of the original meaning of the base word. For example, consider the prefix de-. This prefix means to undo something and is usually attached to a verb. Using this prefix, you can take the verb activate, which means to put something to use, and change it to deactivate, which means to take something out of use.
| Prefix | Meaning | Examples |
| a- | lacking, without, not | amoral, atheist, abiotic |
| ab- | away, removed, not | abnormal, abstract, absent |
| an- | without, not, lacking | anaerobic, anacoustic, anhydrous |
| anti- | against, opposing, contrary to | antibiotic, antifreeze, antisocial |
contra- |
contrary to, against, opposing | contraindicated, contralateral, contraflow |
| counter- | opposing, contrary to, against | counterproposal, counteroffer, counter-attack |
| de- | reverse, undo, remove | deactivate, de-ice, deplane |
| dis- | remove, separate, apart from | disagree, disapprove, disconnect |
| ex- | away from, former, lacking | ex-husband, ex-wife, ex-boss |
| il- | not, lacking, without | illegal, illegible, illogical |
| im- | without, not, lacking | impossible, improper, impermeable |
| in- | no, without, lacking | injustice, incomplete, invisible |
| ir- | not, non, opposite | irreversible, irreplaceable, irregular |
| non- | not, lacking, without | nonexistent, nonfiction, nonnegotiable |
| un- | opposite, not, lacking | unkind, unresponsive, unruly |
25 Common Prefixes in English With Examples
There are many prefixes that don't negate the original meaning of the root word, but rather alter it in unique ways, such as expressing relationships of time, place or manner. Prefixes are sometimes added to complete English words or to root word stems that can be traced to Latin or Greek.
| Prefix | Meaning | Examples |
| ante- | before, prior to, front | antebellum, antechamber, anterior |
| auto- | self, one's self, yourself | autobiography, autograph, autonomy |
| circum - | around, go around | circumnavigate, circumscribe, circumvent |
| co- | jointly, with, together | coexist, copilot, coworker |
| com- | together, with | commiserate, compartment, community |
| con- | with, together | confound, confluence, conversation |
| en- | put into, surround | encase, endow, envelope |
| exo- | out, outer | exhale, extend, exoskeleton |
| extra- | beyond, more | extracurricular, extraterrestrial, extravert |
| hetero- | different, not the same | heterogeneous, heterosexual, heterocyst |
| homo- | same, not different | homogenize, homophone, homosexual |
| hyper- | extreme, beyond | hyperactive, hyperspace, hypertension, |
| inter- | between, in the midst of, among | intermittent, intersect, interstate |
| mega - | large, massive | megaphone, megadose, megabyte |
| micro- | small, tiny | microcosm, microphone, microscope |
| mid- | middle. midpoint | midnight, midseason, midterm |
| mis- | incorrect, bad, wrongful | misappropriate, misunderstand, misuse |
| mono- | one, singular | monogamous, monotone, monochrome |
| over- | too much, excessive | overcook, overdone, overwrought |
| post- | after | postdate, postscript, post-war |
| pre- | before, prior to | prefix, preliminary, preschool |
| re- | again, do over | reconsider, re-evaluate, rewrite |
| semi- | partial, somewhat, less than fully | semiconductor, semester, semi-retired |
| sub- | below, beneath | subjugate, submarine, sub-par |
| trans- | across, change | transferrence, transgender, translate |
Expand Your Vocabulary With Prefixes
Prefixes are a powerful tool in the English language. Learning about common prefix examples and how to use them will help you strengthen your vocabulary and develop the ability to vary the language you use in your writing and conversations. Remember that some prefixes can share a meaning, such as il-, in-, im- and ir-, and that you do not generally hyphenate a prefix unless it’s attached to a proper noun (though there are some exceptions, as illustrated by a few of the examples in the tables). Once you have mastered these prefixes, it's much easier to figure out the meaning of new words when you come across them.
Now that you've mastered some common prefix examples, next you'll want to study a selection of suffixes. Boost your skills by practicing with roots, base words, prefixes, and suffixes. Once you master these, there will be no limit to your language arts learning and what you can do with your English language skills.