A statement, which is used to describe a person (most commonly a friend) who is about to partake in an action of unpleasantry an annoyance. It pretty much means you wanna fight them.
Friend 1: "Dude, I'm gonna eat the last Ice Cream bar."
Friend 2: "I will murk you if you do so, faggot."
Friend 2: "I will murk you if you do so, faggot."
by NateDoggeh February 14, 2017