Page 21 - English Vocabulary in Use (Pre & Intermediate)

a Prefixes

With the meaning ‘not’
Prefixes (un-, in-, il-, ir-, and dis-) are often used to give adjectives (and some verbs and
nouns) a negative meaning. Here are common examples:
happy unhappy like (v) dislike (v)
possible impossible legal illegal (= against the law)
correct incorrect regular irregular, e.g. irregular verbs
un- is used with many different words, e.g. unfriendly, unable, unemployed (= without a
job), untidy (= not in order; in a mess)
im- is used before some words beginning with m or p, e.g. impolite (= rude), impatient
(somebody who is impatient wants things to happen now; they cannot wait for things)
il- is used before some words beginning with ], e.g. illegible (= cannot be read because the
writing is very bad)
ir- is only used before some words beginning with r, e.g. irresponsible
dis- is used before some adjectives, e.g. dishonest, and a few verbs, e.g. dislike, disagree
in- is used before a limited number of words, e.g. invisible (= cannot be seen)
Note: A prefix does not normally change word stress, e.g. happy/unhappy; possible/
impossible. But the stress may change if you want to emphasise the negative or opposite:
A: Was he happy about the change?
B: No, he was very unhappy about it.

Verb prefixes: un- and dis-
These prefixes have two meanings: they can have a negative meaning (as above), but they
can also mean ‘the opposite of an action’ or ‘to reverse an action’. This meaning is used
with certain verbs.
I locked the door when I left, but I lost the key, so I couldn’t it unlock it when I got back.
I had to pack my suitcase (= put everything in it) very quickly, so when I unpacked (= took
everything out) at the hotel, most of my clothes looked terrible.
The plane appeared in the sky, then suddenly disappeared behind a cloud.
In the morning you get dressed (= put on your clothes); when you go to bed you get
undressed (= take off your clothes).

Other verb prefixes with specific meanings

re- (= again) My homework was terrible, so I had to redo it.
The shop closed down but will reopen next month.
I failed my exam but I can retake (or redo/resit) it next year.
over- (= too much) I think my boss is overdoing it at the moment. (= working too hard;
also overwork)
I went to bed very late and I overslept (= slept too long) this morning.
The shop assistant overcharged me. (= asked me for too much money)
mis- (= badly or I’m afraid I misunderstood what he said.
incorrectly) Two of the students misread the first question.

18 English Vocabulary in Use (pre-intermediate & intermediate)