"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!"
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.
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. . ."