beat the pants off someone
beat the hell out of (someone)
1. To deliver a violent and prolonged physical attack. This phrase can be used both literally and hyperbolically. Our neighbor is in the hospital because a burglar beat the hell out of him. I'm worried that the captain of the football team will beat the hell out of me if he finds out that I'm secretly seeing his girlfriend. If you ever scare me like that again, I'll beat the hell out of you, I swear!
2. To defeat an opponent decisively. The final score was 17-1? Wow, we really beat the hell out of that team!
beat the pants off someoneor
beat someone's pants offINFORMAL
If you beat the pants off someone or if you beat their pants off, you defeat them completely in a contest or competition. He brought out a chess board. `Now, Smith, I'm going to beat your pants off'. The non-academic children usually beat the pants off the rest at sport and technical work.