late 14c., "to gallop," possibly from Old North French *waloper (13c., Old French galoper), from Frankish compound *walalaupan "to run well" (compare Old High German wela "well," see well, adv.; and Old Low Franconian loupon "to run, leap," from Proto-Germanic *hlaupan; see leap, v.). The meaning "to thrash" (1820) and the noun meaning "heavy blow" (1823) may be separate developments, of imitative origin. Related: Walloped; walloping.