It is the amalgamation of being a bro, and being on the roam. Bro's Roaming, broaming. Commonly used in the game Darkfall Online.
Whiny Baby Zealot: Why do you guys sit in your hamlet dueling like fags all day when you could be out roaming for mad pvp?!
Baller DHW: Looks like Zealot's on the roam again. Just some bro's roamin', broamin' it. Hope they find pvp so their vagina's stop bleeding.