Answer: flapping

AnswerCrossword Clue
flapping(of something attached at one point or loosely fastened) Flutter or wave around
flappingMove (one's arms or hands) up and down or back and forth
flapping(of a bird) Move (its wings) up and down when flying or preparing to fly
flappingthe act of flapping
flappingWave (something, esp. a cloth) around or at something or someone
flappingStrike or attempt to strike (something) loosely with one's hand, a cloth, or a broad implement, esp. to drive it away