whop
Concise Oxford English Dictionary © 2008 Oxford University Press:
whop /wɒp/ (chiefly N. Amer. also whap) informal
▶verb (whops, whopping, whopped) hit hard. ▶noun a heavy blow or its sound.
■ the regular pulsing sound of a helicopter rotor.
– origin ME: var. of dial. wap ‘strike’, of unknown origin.
'whop' also found in these Oxford entries:

