The definition of ubad bro comes from the online gaming world of having either a bad teammate or enemy and then calling them your bro afterwards. It has become really popular since ubad and bro are both often used when talking online trash.
Person A: WTF! you stole my kill! $@#* KSer!

Person B: lolol ubad bro! Not my fault you couldn't kill em first!
by Weba February 20, 2012
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