Flap  —v. (-pp-) 1 move or be moved up and down; beat. 2 colloq. Be agitated or panicky. 3 sway; flutter. 4 (usu. Foll. By away, off) strike (flies etc.) With flat object; drive. 5 colloq. (of ears) listen intently. —n. 1 piece of cloth, wood, etc. Attached by one side esp. To cover a gap, e.g. A pocket-cover, the folded part of an envelope, a table-leaf. 2 motion of a wing, arm, etc. 3 colloq. Agitation; panic (in a flap). 4 aileron. 5 light blow with something flat.  flappy adj. [probably imitative]