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!"
1. A guy, specifically your "friend", who is always attempting to upstage you (whether he does so or not). This is especially true around the opposite gender.
2. A male who performs many dick moves, usually harmless.
Also: antibros tend to only be a bro off and on, after all if they were constantly an attention whore they wouldn't be able to fall into the category of bro at all.
Often times an antibro is a compulsive liar, or may just be flaunting how bad ass he thinks he is.
Henry: "Man, today that lecture was crazy, wanna go for lunch?"
Antibro: "By the way, I took three different naps with three different girls in your bed."
Henry: ". . ."
Guy #1: "Hmm. . . I just stapled my arm twice. . ."
Girls in room: "HOLY CRAP!?!?"
Antibro: "I would totally staple my arm too!"
Guy#1: "DO IT FAGGOT. BTW can I have a paper towel?"
Antibro: "I would but you already did it. I still might. . ."
awful friend; friend who often does not uphold is end of the friendship
"Aw man Kaden is off with his girlfriend again...he's such an anti-bro."