kick someone's ass

kick ass

1. verb, rude slang To defeat someone or something decisively. In this usage, a possessive noun or pronoun is used between "kick" and "ass." We weren't prepared for that game, and the other team kicked our asses.
2. verb, rude slang To physically attack one; to beat one up. In this usage, a possessive noun or pronoun is used between "kick" and "ass." I'll kick your ass if I ever see you talking to my girlfriend again.
3. verb, rude slang To be very effective or successful. This new strategy is really kicking ass and keeping the groundhogs away from my vegetable garden!
4. verb, rude slang To be excellent or exceptional. That move kicked ass! All movies should be like that!
5. verb, rude slang To motivate one or shock one out of complacency. In this usage, a possessive noun or pronoun is used between "kick" and "ass." The professor's speech today kind of kicked my ass and made me realize I need to start applying myself.
6. adjective, rude slang Excellent or exceptional; awesome. In this usage, the phrase is hyphenated or spelled as one word. That was a pretty kick-ass rollercoaster. Whoa, check out that kickass bike.
See also: ass, kick

kick someone's ass

or

kick someone's butt

mainly AMERICAN, INFORMAL, RUDE
1. If someone kicks your ass, they attack you or punish you. Dad would have kicked my ass for allowing you to sleep here. We can kick his butt if he gets out of line.
2. If someone kicks your ass, they defeat you easily in a competition. There are guys who won't qualify for the Open who could kick my ass most days. The Chicago team played tough there, let's kick their butt when they come here. Note: `Ass' and `butt' are informal American words for `bottom'.
See also: ass, kick

kick someone's ass (or butt)

dominate, beat, or defeat someone. North American vulgar slang
See also: ass, kick