The prefix anti- means which of the following?

• A. Against or opposite.
• B. For or in favor of.
• C. Across or beyond.
• D. Within or inside.

Answer: (A)

Anti- signals opposition. When you see this prefix, think “against” or “the opposite of.” It’s used to convey that something is opposed to or counteracts what follows. For example, antifreeze protects a substance from freezing, antibiotics fight off bacteria, and antisocial behavior goes against what’s typical in social interactions. This sense of opposition is what anti- consistently communicates. Other prefixes map to different ideas: pro- means in favor of, trans- means across or beyond, and intra- (or within) means inside. Those meanings don’t match the idea of opposition, so they don’t fit anti-.