Prefixesare 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 wasunableto attend the meeting.
Non-paymentof fees could result in a student being asked to leave the course.
Has anyone ever really met anextraterrestrialbeing?(meaning a being from another planet)
The meat wasovercookedand 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-heroorsupermodel)
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.