PREFIXES

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. 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,