Do you know ghouls from goblins and ghosts?
1924, from wise (adj.) + crack in the "boast" sense (see cracker).
A witty remark, esp one with a knowing, sarcastic edge; a joke; gag, one-liner: at least two wisecracks in the first paragraph/ makers of wars and wise-cracks, a rum creature
[1924+; perhaps fr the theatrical term crack a wheeze, ''tell a joke'']