A glass of wine given out of turn, the bottle having been handed backwards.

A blow with the back of the hand.

(informal) A bribe, a secret payment.

(racquet sports) A shot played backhand, a backhand stroke.

(racquet sports) A player who plays a backhand shot.

(surfing) A surfer who approaches a swell with the wave behind them ("on their backhand") rather than facing the wave ("on their forehand").