Do you know ghouls from goblins and ghosts?
1690s, perhaps from crompid cake "wafer," literally "curled-up cake" (1382; Wyclif's rendering of Hebrew raqiq in Ex. 29:23), from crompid, past participle of crumpen "curl up." Alternative etymology is from Celtic (cf. Breton krampoez "thin, flat cake"). Slang meaning "woman regarded as a sex object" is first recorded 1936.