A phrase coined and popularized by the band thrash metal band Lich King. Something you yell in a mosh pit,(usually at a metal show) when you want to kick a poser's ass, or get other people to help you take down someone being a bully in the pit.
Guy who's being an asshole tries to start a fight with everyone instead of having a good time.
*Person tired of the bully's shit* COMBAT MOSH!!!
Bully gets wrecked.
Originally coined by the thrash metal band Lich King, "Combat Mosh" is normally yelled out in mosh pits at metal shows. It is a call to action to others in the pit to beat someone up, normally because they're being a dick (targeting, hardcore dancing, etc.). Combat Moshing normally happens in large groups so participant's can't really be singularly targeted and thrown out.
Headbanger 1: Hey man, you see that asshole windmilling over there?
Headbanger 2: You're damn right I do!
Both: COMBAT MOSH!!!
*guy gets his ass beat*