Someone who is the opposite of a bro. He does not chill at all, does not play lax, does not pack D's, does not mack breds, and ruins everything. The anti is to be avoided at all costs.
"Dude when Male spilled the brew all over my couch he became the biggest anti-bro in the world."
Guy 1: "Yo did you hear what Chuck did?"
Guy 2: "Yeah, he cockblocked me from hooking up with his sister."
Guy 1: "What a total anti-bro!"