Some one who is well aware that what he is doing is wrong or out of place but continues to do it anyway. The more he notices that his actions are irritating it invoke more of their obnoxious behavior. See Ignorant Bitch for Female definition
A man on the Subway is talking loudly on his cell phone. He looks around and sees and old lady rolling her eyes he smiles and gets louder. Someone whispers I wish that Ignorant Bastard would shut up.
ignore anti-social Rude
Guy1: All our fucking Physics teacher does is talk about religion and other shit Guy2: Yeah I have him for freshman science. He sure is an Ignorant Bastard.
