quite simply, Friend Of Girl... a guy who simply can not seal the deal with the ladies, or one who tries to be friends first and then develop the relationship but fails in the latter.
"fresh out of grade school." Basically, a grade nine, or when someone acts immature. It is interchangeable with the term "niner" only FOG is more fun to say...
-(Let's say Jill is acting immature), One may say, Jill is so FOG.
/fôɡ/ : a friend of the gays; or questionably straight men with perfect hair and impeccable style who partake in activities such as shopping and SoulCycle, and appear to be gay in every way, but have girlfriends.
A: "My boyfriend loves to shop! We go shoppingtogether all the time..."
B: "He sounds like a fog to me."
Ex: You've got to kiss a lot of fogs before you'll find your prince.