Which prefix means "not" and is commonly used to form antonyms?

Which prefix means "not" and is commonly used to form antonyms?

• A. Anti-
• B. Pre-
• C. Un-
• D. Re-

Answer: (C)

A prefix that means not and signals opposite meaning is un-. When you attach un- to a word, you negate it and show the opposite sense: happy becomes unhappy, clear becomes unclear, healthy becomes unhealthy. This direct negation is what makes un- the typical choice for forming antonyms. Other prefixes don’t fit as neatly: pre- means before, re- means again or back, and anti- means against in a sense of opposition rather than simply “not.”

A prefix that means not and signals opposite meaning is un-. When you attach un- to a word, you negate it and show the opposite sense: happy becomes unhappy, clear becomes unclear, healthy becomes unhealthy. This direct negation is what makes un- the typical choice for forming antonyms. Other prefixes don’t fit as neatly: pre- means before, re- means again or back, and anti- means against in a sense of opposition rather than simply “not.”