Word formation

Negative prefixes

Prefixes like in-, un- and dis- can be added to some adjectives, adverbs, verbs and nouns to give them a negative meaning.

• Improving your performance with drugs is unfair.
• We're used to seeing athletes, cyclists and swimmers disqualified.
• They unrealistically thought that they would finish the project on time.
• His insincerity made him very unpopular.

Here are more common examples of words with these prefixes:

In-

inactive, inadvisable, inappropriate, incapable, inefficient, inexperienced

Un-

unauthorised, unable, unacceptable, unbearable, unbelievable, undetectable, unexpected, unhealthy, unnecessary, unofficial, unpopular, unpredictable, unreasonable, unrepeatable, unsafe, unsuccessful

Dis-

disagree, disappear, disappoint, disapprove, dishonest, disqualified

Also, the prefixes il-, im- and ir- can be used in this way. Often, they combine like this:

• il- before adjectives and adverbs that start with l: illegal
• im- before adjectives and adverbs that start with b, m or p: impossible
• ir- before adjectives and adverbs that start with r: irresponsible

Here are more common examples of words with these prefixes:

Il-

illegal, illegible, illegitimate, illicit, illiterate, illogical

Im-

imbalance, immobile, immodest, immoral, immortal, impatient, imperfect, impolite, impossible, impractical, improbable

Ir-

irrational, irregular, irrelevant, irresistible, irresponsible, irreversible