kick butt
(spoken) to be very exciting or effective kick ass The new system really kicked butt, catching several cheaters the first day it was used.
kick (somebody's) butt
also kick some butt1. to fight someone and hurt them kick (somebody's) ass Lyle claimed she could kick my butt, and then decided she had better start training in case anybody asked her to prove it. The cops in this city don't just want to kick down doors and kick some butt.
2. to defeat someone completely kick (somebody's) ass Even when Barry was hurting, he was not only on the field but also kicking butt. We hope they come back because we want to kick their butt again.
kick (some) butt (and take names)
See: kick (some) ass (and take names)