Crack up (5)

I think it could be either:

Which length description are you looking for?:

laugh

'crack up' is the definition.
(I've seen this in another clue)

This is all the clue.

(Other definitions for laugh that I've seen before include "Sound of mirth" , "Cachinnate" , "scream?" , "Break up" , "a ridiculous thing" .)

I've seen this clue in The New York Times, the King Feature Syndicate, the Newsday and The Globe and Mail.

Want a hint initially instead of a full solution? Install my app