1. superlative form of crazy; most mentally ill or unstable
Usage: can be offensive when referring to mental illness
2. superlative form of crazy; most extremely foolish or irrational
Usage: informal
3. superlative form of crazy; most extremely enthusiastic or excited
Usage: informal

Examples

• That was the craziest movie I’ve ever seen.
• She had the craziest idea for the school fundraiser.
• The fans went the craziest when their team scored.
• It was the craziest storm we’d experienced in years.
• He’s the craziest driver on the highway.
• That’s the craziest excuse I’ve ever heard.
• The party got craziest around midnight.