Marked by thought or action that lacks reason How to use crazy in a sentence. Crazy (comparative crazier, superlative craziest) of unsound mind [from 17th c.] synonym quotations synonyms Insane his ideas were both frightening and crazy. 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). 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 mean insane, though in today's world, it is offensive to apply it to those who struggle with mental illness. 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: There are 17 meanings listed in oed's entry for the adjective crazy, two of which are labelled obsolete, and one of which is considered offensive
