sphinx

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Mythology A figure in Egyptian myth having the body of a lion and the head of a man, ram, or hawk.
• noun Greek Mythology A winged creature having the head of a woman and the body of a lion, noted for killing those who could not answer its riddle.
• noun A puzzling or mysterious person.

from The Century Dictionary.

• noun In Greek myth, a female monster, said to have proposed a riddle to the Thebans who passed her as she sat on a rock by the roadside, and to have killed all who were not able to guess it.
• noun In Egyptian antiquity, a figure somewhat similar in composition to the Greek, having the body of a lion (never winged), and a male human head or an animal head.
• noun In heraldry, a creature with a lion's body and a woman's head, but not necessarily like any ancient original. It is assumed to be winged; when not winged, it should be blazoned “sans wings.”
• noun An enigmatic or sphinx-like person; one who talks puzzlingly, or is inscrutable in disposition or character; one whom it is hard to understand.
• noun In entomology:
• noun A hawk-moth; a member of the genus Sphinx or the family Sphingidæ. See cuts under hawk-moth, hog-caterpillar. Lepidoptera, and Philampelus.
• noun The typical genus of the family Sphingidæ.
• noun The Guinea baboon, Cynocephalus papio or Papio sphinx. Also called sphinx-bahoon.

from the GNU version of the Collaborative International Dictionary of English.

• noun In Egyptian art, an image of granite or porphyry, having a human head, or the head of a ram or of a hawk, upon the wingless body of a lion.
• noun On Greek art and mythology, a she-monster, usually represented as having the winged body of a lion, and the face and breast of a young woman.
• noun Hence: A person of enigmatical character and purposes, especially in politics and diplomacy.
• noun (Zoöl.) Any one of numerous species of large moths of the family Sphingidæ; -- called also hawk moth. See also tomato worm.
• noun (Zoöl.) The Guinea, or sphinx, baboon (Cynocephalus sphinx).
• noun (Zoöl.) a large West African baboon (Cynocephalus sphinx), often kept in menageries.
• noun (Zoöl.) Same as Sphinx, 3.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun mythology A creature with the head of a human and the body of an animal (commonly a lion).
• noun A person who keeps his thoughts and intentions secret.
• noun rare A sphincter.
• verb To decorate with sphinxes.
• verb To adopt the posture of the Sphinx.
• verb To be inscrutable, often through silence.
• verb To make one guess at the unknowable
• verb To befuddle.
• verb For the feminine to co-opt, dominate, or devour the masculine, especially from a paranoid fear of this happening

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun an inscrutable person who keeps his thoughts and intentions secret
• noun (Greek mythology) a riddling winged monster with a woman's head and breast on a lion's body; daughter of Typhon
• noun 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