noun

• (anatomy) The area encompassing the upper thigh, hip and buttocks on one side of a human, primate, or quadruped animal, especially one that can sit on its hindquarters.
  "But I had no time to pursue these reflections; for the gray horse came to the door, and made me a sign to follow him into the third room where I saw a very comely mare, together with a colt and foal, sitting on their haunches upon mats of straw, not unartfully made, and perfectly neat and clean."
• (architecture) A squat vertical support structure.
• (dialect) A jerked underhand throw.

verb

• (transitive, architecture) To provide with a haunch or supporting structure.
• (transitive, dialect) To throw with an underhand movement.