thumper noun. ['Ɵʌmpǝ] M16.
[from THUMP verb + -ER¹.]
1. a. A person who or thing which thumps something. M16.
Ambit Behind the arrogant chest-thumper there was a humble and kindly man.
b. Geology. A device for creating artificial seismic waves in the earth. M20.

2. A strikingly big thing of its kind, esp. a blatant or gross lie. colloq. M17.
■ J. Collins They gives me a Thumper of a Christmas Box.

3. A thumping or heavy blow. Long rare or obsolete. L17.

4. A motorcycle or trail bike designed to travel over rough terrain, esp. one with a single-cylinder, four-stroke engine which produces a characteristic 'thump' on the fourth power-stroke of the piston. colloq. L20.

[TahlilGaran] English Dictionary ▲