Wapper
Wap"per\, v. t. & i. [freq. of wap, v.; cf. dial. G. wappern, wippern, to move up and down, to rock.] To cause to shake; to tremble; to move tremulously, as from weakness; to totter. [Obs.]Wapper
Wap"per\, n. (Zo["o]l.) A gudgeon. [Prov. Eng.]