"a hit, a blow," late 14c., probably of imitative origin. The verb (late 14c.) originally meant "to throw quickly or with violence," and in slang c. 1560-1730 it meant "to copulate." Related: Wapped; wapping.
Entries linking to wap
whop v.
"to beat, strike," mid-15c., of imitative origin. Compare Welsh chwap "a stroke," also of imitative origin; also see wap. Related: Whopped; whopping.