sphinx \'sfing(k)s\ n, pl sphinxes or sphinges \'sfing-,jez\ [L, fr. Gk; aking to Gk sphinkter sphincter] 1 a often cap : a femal monster having according to Greek mythology a lion's body and a human head and having the habit of asking a riddle and killing anyone who failed to answer it b : an enigmatic or mysterious person 2 : an ancient Egyptian image in the form of a recumbent lion having a man's head, a ram's head, or a hawk's head 3 : HAWKMOTH