Etymology
From onychophagy + -ist = onycho- + -phag(y) + -ist, from Ancient Greek ὀνυχο- (onuch), combining form of ὄνυξ (ónux, “claw, nail”) + -φαγος (-phagos, “eater”), from ἐφαγόν (ephagón, “I ate”).
Definitions & examples from Wiktionary (CC BY-SA 3.0).