Prefixes

A prefix is placed at the beginning of a word to modify or change its meaning. This is a list of the most common prefixes in English, together with their basic meaning and some examples. You can find more detail or precision for each prefix in any good dictionary.

A prefix goes at the beginning of a word. A suffix goes at the end of a word.

The origins of words are extremely complicated. You should use this list as a guide only, to help you understand possible meanings. But be very careful, because often what appears to be a prefix is not a prefix at all. Note also that this list does not include elements like "auto-" or " bio-", because these are "combining forms", not prefixes.

prefix meaning examples
a- also an- not, without atheist, anaemic
a- to, towards aside, aback
in the process of, in a particular state a-hunting, aglow
a- of anew
completely abashed
ab- also abs- away, from abdicate, abstract
ad- also a-, ac-, af-, ag- al-, an-, ap-, at- as-, at- movement to, change into, addition or increase advance, adulterate, adjunct, ascend, affiliate, affirm, aggravate, alleviate, annotate, apprehend, arrive, assemble, attend
ante- before, preceding antecedent, ante-room
anti- also ant- opposing, against, the opposite anti-aircraft, antibiotic, anticlimax, Antarctic
be- all over, all around bespatter, beset
completely bewitch, bemuse
having, covered with bejewelled
affect with (added to nouns) befog
cause to be (added to adjectives) becalm
com- also co-, col-, con-, cor- with, jointly, completely combat, codriver, collude, confide, corrode
contra- against, opposite contraceptive
counter- opposition, opposite direction counter-attack, counteract
de- down, away descend, despair, depend, deduct
completely denude, denigrate
removal, reversal de-ice, decamp
dia- also di- through, across diagonal
dis- also di- negation, removal, expulsion disadvantage, dismount, disbud, disbar
en- also em- put into or on engulf, enmesh
bring into the condition of enlighten, embitter
intensification entangle, enrage
ex- also e-, ef- out exit, exclude, expand
upward exalt, extol
completely excruciate, exasperate
previous ex-wife
extra- outside, beyond extracurricular
hemi- half hemisphere
hyper- beyond, more than, more than normal hypersonic, hyperactive
hypo- under hypodermic, hypothermia
in- also il-, im- not, without infertile, inappropriate, impossible
also il-, im-, ir- in, into, towards, inside influence, influx, imbibe
infra- below infrared, infrastructure
inter- between, among interact, interchange
intra- inside, within intramural, intravenous
non- absence, negation non-smoker, non-alcoholic
ob- also oc-, of-, op- blocking, against, concealing obstruct, occult, offend, oppose
out- surpassing, exceeding outperform
external, away from outbuilding, outboard
over- excessively, completely overconfident, overburdened, overjoyed
upper, outer, over, above overcoat, overcast
peri- round, about perimeter
post- after in time or order postpone
pre- before in time, place, order or importance pre-adolescent, prelude, precondition
pro- favouring, in support of pro-African
acting for proconsul
motion forwards or away propulsion
before in time, place or order prologue
re- again repaint, reappraise, reawake
semi- half, partly semicircle, semi-conscious
sub- also suc-, suf-, sug-, sup-, sur-, sus- at a lower position submarine, subsoil
lower in rank sub-lieutenant
nearly, approximately sub-tropical
syn- also sym- in union, acting together synchronize, symmetry
trans- across, beyond transnational, transatlantic
into a different state translate
ultra- beyond ultraviolet, ultrasonic
extreme ultramicroscopic
un- not unacceptable, unreal, unhappy, unmanned
reversal or cancellation of action or state unplug, unmask
under- beneath, below underarm, undercarriage
lower in rank undersecretary
not enough underdeveloped