To act like some nutty woman would in that particular situation. To behave precisely like some ignored girlfriend who is bitching at her boyfriend about shit he doesn't care about -- probably stuff that doesn't matter to anyone except her. This is not specifically reserved for women, and in fact is more applicable towards males. To act generally bizarrely, unbalanced and quite possibly overly-feminine in a situation that does not warrant it.
I was just sitting there trying to play some video games when my buddy broaded out on me because I didn't notice he just got a haircut and that his pants make his ass look good. As he was running away, hands flapping and crying, I yelled, "Oh man, don't broad out on me again -- I just lost my last life!"
by A. Nonimouse. January 17, 2010