A hateful word used by uneducated and ignorant homophobes who have a problem with others being gay. It is litterally the same thing as saying cracker or n*gger. It is pretty much discrimination against gays. If you do this, go fuck yourself. Even if it's used as an insult towards a non gay person, there's nothing wrong with being gay.

I couldn’t care less (but one must keep up appearances, right?)