short for "Godfather of Soul", one of the many nicknames of James Brown.
Who doesn't love the GFOS?
Girlfriend Over Shoulder. Said to your fellas online to alert them that the topic of conversation suddenly warrants a window change and that you may bbl to finish said topic, or that the topic needs to change quickly while you make the window smaller.
Mike: yo that chick you were talking to at the bar was hot
Bill: hell yeah dude
Mike: did you get her #?
Bill: shit, gfos
Bill: nice1 brotha