'Flapping' definitions:

Definition of 'flapping'

noun

The motion made by flapping up and down [syn: flap, flapping, flutter, fluttering]

From: GCIDE

Flap \Flap\, v. t. [imp. & p. p. Flapped; p. pr. & vb. n. Flapping.] [Prob. of imitative origin; cf. D. flappen, E. flap, n., flop, flippant, fillip.]
1. To beat with a flap; to strike. [1913 Webster]
Yet let me flap this bug with gilded wings. --Pope. [1913 Webster]
2. To move, as something broad and flaplike; as, to flap the wings; to let fall, as the brim of a hat. [1913 Webster]
To flap in the mouth, to taunt. [Obs.] --W. Cartwright. [1913 Webster]