Word building — prefixes & suffixes
Prefixes change meaning (dis-, re-, over-); suffixes change word type (-ment, -able, -ful), using Unit 24 word parts.
A prefix goes before a base word and changes its meaning (happy → unhappy). A suffix goes after a base word and usually changes its word type — noun, adjective, verb (develop → development).
A — How it works
Negative prefixes: in- (correct), im- before m/p/b (possible), ir- before r (regular), dis- (agree). Other prefixes: re- again, over- too much, pre- before, post- after, co- together.
1) Negative prefixes — in- / im- / ir- / dis-
Choose the prefix based on the first letter of the base word.
- That answer is incorrect.
- It's impossible to finish by tomorrow.
- His attendance has been irregular this term.
- I disagree with the new plan.
2) Other prefixes — re- / over- / pre- / post- / co-
re- = again, over- = too much, pre- = before, post- = after, co- = together.
- Please rewrite the report before Friday.
- He's overworked and needs a holiday.
- Book a preview before the film is released.
- We'll meet in the postwar period of the course.
- She co-wrote the article with a colleague.
3) Suffixes that make nouns — -ment / -ion/-tion / -er/-or / -ist
These turn a verb or idea into a person or a thing.
- The government announced a new development plan.
- We need your decision by Friday.
- My sister is a teacher; my brother is an actor.
- She's a talented artist and a keen cyclist.
4) Suffixes that make adjectives — -able/-ible / -ful / -ous / -al / -ic / -y
These turn a noun or verb into a describing word.
- That old bridge doesn't look very reliable.
- Thank you, that was a really helpful suggestion.
- Driving in that storm was dangerous.
- It was a historic and national celebration.
- It's a cloudy, rainy day again.
The rest of this lesson is in the General English course:
- B — Quick reference
- Remember
Try it: Choose the correct prefix
Select the correct negative prefix.
- That's totally ___possible — nobody can finish it today.
(a) in (b) im (c) ir - His work is very ___regular — some weeks he does none at all.
(a) in (b) im (c) ir - I think that answer is ___correct.
(a) in (b) im (c) ir - We completely ___agree about the new schedule.
(a) in (b) im (c) dis
Check your answers in the course — it marks them instantly. This is one of the unit's 4 exercises; the other 3 are in the General English course too.
Practise this unit in the course →