It means Faggot Basically this was started in World of Warcraft on the Burning Blade (horde) server.

During a SSC Raid we were thinking of new ways to spell "Faggot" So we were about to attempt a boss and some of us still trying to spell Faggot In a different way led to quickly typing "Gaifet" when I really wanted to spell "Faiget"

And thats how it all started.