A woman who frequents gay bars because she is so attractive she does not need to be hit on by drunk straight men to boost her ego, thus she finds it an irritating distraction from a night of hanging out with her equally radiant friends.
Often is confused for the "Lesbian friend" of a gay man, however the distinction should be an easy one since the "Lesbian friend" is 150 pounds heavier then the "Fag Hag" and usually sports a mustache.
Drunk Guy: Hey, lookit that fat, ugly fag hag!
Less Drunk Guy: You mean the one sucking face with that stubby lumberjack?
Drunk Guy: Yeah. Hey is that two women?
Less Drunk Guy: I don't think that's a fag hag.