A person who keeps his/her thoughts and intentions secret; an enigmatic or impassive person.
A sphinx moth.
A sphincter.
A creature with the head of a person and the body of an animal (commonly a lion).
To adopt the posture of the Sphinx.
To decorate with sphinxes.
To be inscrutable, often through silence.
To behave in a manner characteristic of the Sphinx.
A person or thing whose nature or value is a mystery.
Used other than figuratively or idiomatically: see unknown, quantity.