The meaning of CRAZY is not mentally sound : marked by thought or action that lacks reason : insane —not used technically. How to use crazy in a sentence.

Crazy definition: mentally deranged; demented; insane.. See examples of CRAZY used in a sentence.

crazy adjective (INTERESTED) [ after noun ] used for saying that someone thinks about something all the time or wants it very much, in a way that some people might think is extreme:

3 days ago · Use the adjective crazy to describe actions that aren't sensible, like the crazy way your brothers run around the house when their favorite team wins a game. Crazy can also …

CRAZY meaning: 1 : not sane: such as; 2 : having or showing severe mental illness

If you describe someone or something as crazy, you think they are very foolish or strange.

One who is or appears to be mentally deranged: "To them she is not a brusque crazy, but 'appropriately passionate'" (Mary McGrory).

crazy (informal) used to describe someone whose mind does not work normally or whose behavior is very strange or out of control: Have you met the crazy old lady upstairs?

crazy definition: mentally unstable or acting irrationally. Check meanings, examples, usage tips, pronunciation, domains, and related words. Discover expressions like "girl crazy", "be crazy …

Aug 5, 2025 · Definition: The state or quality of being crazy; wild or irrational behavior or thinking. Synonyms: insanity, madness, lunacy, derangement, eccentricity, fanaticism, obsession