Wap'per transitive verb & i. [ freq. of wap , v.; confer dial. German wappern , wippern , to move up and down, to rock.] To cause to shake; to tremble; to move tremulously, as from weakness; to totter. [ Obsolete]
Wap'per noun (Zoology) A gudgeon. [ Prov. Eng.] 
• (n.) A gudgeon. • (v. t. & i.) To cause to shake; to tremble; to move tremulously, as from weakness; to totter.