early 14c., cromplen, crumplen, "press into irregular folds, rumple, wrinkle," also intransitive, "contract into wrinkles, shrink, shrivel," frequentative of crumpen "to curl up" (from Old English crump "bent, crooked"), from Proto-Germanic *krumbo- "to press, squeeze, compress" (source also of German krumm "crooked, warped"). Related: Crumpled; crumpling.
sort of tea-cake, 1690s, perhaps from crompid cake "wafer," literally "curled-up cake" (1382; Wyclif's rendering of Hebrew raqiq in Exodus xxix.23), from crompid, past participle of crumpen "curl up" (see crumple (v.)). Alternative etymology is from Celtic (compare Breton krampoez "thin, flat cake"). Slang meaning "woman regarded as a sex object" is first recorded 1936.