beat the pants off someone
beat the pants off (of) (someone)
slang To defeat someone decisively in a competition. Despite using the word "pants," this phrase does not involve literally stripping off someone's clothes. The final score was 17-1? Wow, we really beat the pants off that team!
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
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.
Collins COBUILD Idioms Dictionary, 3rd ed. © HarperCollins Publishers 2012