Wiktionary
alt. 1 (context idiomatic US Canada colloquial English) To be very impressive. 2 (context idiomatic US Canada colloquial English) To beat someone in a competition, fight, or other situation. 3 (context idiomatic US Canada colloquial English) To beat someone in a fight. interj. (context slang English) Used to express happiness or a feeling of accomplishment. vb. 1 (context idiomatic US Canada colloquial English) To be very impressive. 2 (context idiomatic US Canada colloquial English) To beat someone in a competition, fight, or other situation. 3 (context idiomatic US Canada colloquial English) To beat someone in a fight.
Wikipedia
"Kick Ass (We Are Young)" is a song by British singer and songwriter Mika and Moroccan-Swedish record producer RedOne released as a single from the soundtrack to the film Kick-Ass. It was released on 2 May 2010.
Usage examples of "kick ass".
I knew when he looked at me that this was our regular Arty, ready to kick ass by remote control.