From WordNet (r) 3.0 (2006):
flap
n 1: any broad thin and limber covering attached at one edge;
hangs loose or projects freely; "he wrote on the flap of
the envelope"
2: an excited state of agitation; "he was in a dither"; "there
was a terrible flap about the theft" [syn: dither,
pother, fuss, tizzy, flap]
3: the motion made by flapping up and down [syn: flap,
flapping, flutter, fluttering]
4: a movable piece of tissue partly connected to the body
5: a movable airfoil that is part of an aircraft wing; used to
increase lift or drag [syn: flap, flaps]
v 1: move in a wavy pattern or with a rising and falling motion;
"The curtains undulated"; "the waves rolled towards the
beach" [syn: roll, undulate, flap, wave]
2: move noisily; "flags flapped in the strong wind"
3: move with a thrashing motion; "The bird flapped its wings";
"The eagle beat its wings and soared high into the sky" [syn:
beat, flap]
4: move with a flapping motion; "The bird's wings were flapping"
[syn: beat, flap]
5: make a fuss; be agitated [syn: dither, flap, pother]
6: pronounce with a flap, of alveolar sounds