ETYM Latin, from Greek sphigx, usually derived from sphiggein to bind tight or together, as if the Throttler.
1. An inscrutable person who keeps his thoughts and intentions secret.
2. One of a number of large stone statues with the body of a lion and the head of a man that were built by the ancient Egyptians.

(Greek mythology) A riddling winged monster with a woman's head and breast on a lion's body; daughter of Typhon.
Mythological creature, represented in Egyptian, Assyrian, and Greek art as a lion with a human head. In Greek myth the Sphinx killed all those who came to her and failed to answer her riddle about what animal went firstly on four legs, then on two, and lastly on three: the answer is humanity (baby, adult, and old person with stick). She committed suicide when Oedipus gave the right answer.
The Great Sphinx at Gizeh, Egypt, 58 m/189 ft long, was built about 2900–2750 BC.