kicker

noun

• 1a person or animal that kicks: the horses were either biters or kickers
• the player in a team who scores or gains positional advantage by kicking.

• 2North American informal an unexpected and unwelcome discovery or turn of events:the kicker was you couldn’t get a permit
• an extra clause in a contract: Hale added a kicker to the mortgage

• 3 informal a small outboard motor.

• 4(in poker) a high third card retained in the hand with a pair at the draw.