A person who automatically hates on anyone who is not part of their group, or who may be competition for them now or potentially in the future. Someone who automatically hates based upon prejudicial information.
Lisa: That girl just gave me the evil eye for no reason, I don't even know her. All I did was go up to the bar and order a drink.
Leslie: Oh, girl don't trip. I know her, she is a straight Autohater when she's hangin with her crew.