Cambridge Dictionaries online Cambridge Dictionaries online

The most popular online dictionary and thesaurus for learners of English

Prefixes

from English Grammar Today

Prefixes are letters which we add to the beginning of a word to make a new word with a different meaning. Prefixes can, for example, create a new word opposite in meaning to the word the prefix is attached to. They can also make a word negative or express relations of time, place or manner. Here are some examples:

base word

prefixed word

type of meaning

possible

impossible

opposite

able

unable

opposite/negation

payment

non-payment

negation

war

pre-war

time (before)

terrestrial

extraterrestrial

place (outside of/beyond)

cook

overcook

manner (too much)

I’m sorry I was unable to attend the meeting.

Non-payment of fees could result in a student being asked to leave the course.

Has anyone ever really met an extraterrestrial being? (meaning a being from another planet)

The meat was overcooked and quite tasteless.

The most common prefixes

prefix

meaning

examples

anti-

against/opposed to

anti-government, anti-racist, anti-war

auto-

self

autobiography, automobile

de-

reverse or change

de-classify, decontaminate, demotivate

dis-

reverse or remove

disagree, displeasure, disqualify

down-

reduce or lower

downgrade, downhearted

extra-

beyond

extraordinary, extraterrestrial

hyper-

extreme

hyperactive, hypertension

il-, im-, in-, ir-

not

illegal, impossible, insecure, irregular

inter-

between

interactive, international

mega-

very big, important

megabyte, mega-deal, megaton

mid-

middle

midday, midnight, mid-October

mis-

incorrectly, badly

misaligned, mislead, misspelt

non-

not

non-payment, non-smoking

over-

too much

overcook, overcharge, overrate

out-

go beyond

outdo, out-perform, outrun

post-

after

post-election, post-war

pre-

before

prehistoric, pre-war

pro-

in favour of

pro-communist, pro-democracy

re-

again

reconsider, redo, rewrite

semi-

half

semicircle, semi-retired

sub-

under, below

submarine, sub-Saharan

super-

above, beyond

super-hero, supermodel

tele-

at a distance

television, telepathic

trans-

across

transatlantic, transfer

ultra-

extremely

ultra-compact, ultrasound

un-

remove, reverse, not

undo, unpack, unhappy

under-

less than, beneath

undercook, underestimate

up-

make or move higher

upgrade, uphill

Writing prefixes: hyphens (super-hero or supermodel)

There are no absolute rules for when to use a hyphen or when to write a prefixed word as one whole word (see the examples in the table). A good learner’s dictionary will tell you how to write a prefixed word.

(“Prefixes” from English Grammar Today © Cambridge University Press. Need grammar practice? Try English Grammar Today with Workbook.)
Add Cambridge dictionaries to your browser to your website

Word of the Day

first:

(a person or thing) coming before all others in order, time, amount, quality, or importance

Word of the Day

Countability – grammar codes

by Dom Glennon​​,
November 26, 2014
Advices and informations Have you ever noticed strange codes in square brackets on entries in Cambridge Dictionaries Online and wondered what they mean? These are grammar codes, giving you a brief summary of how that word behaves grammatically. More information can be obtained by hovering your cursor over the code, and there’s

Read More 

ped-text verb

November 24, 2014
to text someone while walking I’m ped-texting, I’m looking down at my phone, 75 percent of the time.

Read More