Antonym prefixes reverse the meaning of a word. English has several negative prefixes — un-, in-, im-, il-, ir-, dis-, mis-, non- — and choosing the correct one depends on the word. There are patterns, but also exceptions that must be memorized.
Practice
The instructions were completely ___ — nobody knew what to do.
Sheagreed with the committee's decision.
Put the words in the correct order:
Parking here is ___.
Changing the past is completely.
Put the words in the correct order:
She ___ what I said and thought I was being rude.
The charity is aorganization.
Put the words in the correct order:
His behavior at the meeting was utterly.