I haven't looked up this word, I warn you, so I've just worked it out from context but:
when you have a flat tyre c'est crevé.
when you want to tell someone to drop dead (I know you don't, of course) Crève!
when you feel under the weather, exhausted, generally below par, j'ai la crève
when you are exhausted and desperate for sleep, je suis crevé