1. To beat up. While I was away at camp, I didn't miss my older brother whomping on me and giving me noogies whenever Mom's back is turned.
2. To defeat, especially decisively. We had high hopes going into the game, but the other team totally whomped on us, giving us our first loss.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.