E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Bouncer.
Thats a bouncer. A gross exaggeration, a braggarts lie. (Dutch, bonz, verb bonzen, to bounce or thump. A bouncing lie is a thumping lie, and a bouncer is a thumper.)
1
He speaks plain cannon, fire, and smoke, and bounce.Shakespeare: King John, ii. 2.