/hwop, wop/ , v. , whopped, whopping , n. Informal.
v.t.
1. to strike forcibly.
2. to defeat soundly, as in a contest.
3. to put or pull violently; whip: to whop out a book.
v.i.
4. to plump suddenly down; flop.
n.
5. a forcible blow.
6. the sound made by it.
7. a bump; heavy fall.
Also, whap, wap .
[ 1350-1400; ME, var. of WAP ]