Acronym for Broken Ankle Bitch, an individual who through some sort of accident or mistake has either broken their ankle or sprained it in such a way that they are no longer able to walk in a way that could be considered normal. The injured person has not fully healed and often complains about the injury to friends and family members thus the, "Bitch" component has been added for due measure. See also; S.A.B.
Look at that B.A.B.! He can't even put pressure on his ankle.