(n.)any female friend
(n.)a girl or young woman with whom a man is romantically involved
I love my g-friend.
Even when she rips out my heart.
This is a girl that is a guy's very good friend. At any time they could date, if one asked the other they would go out.
John: Hey man do you want to go hang out with some girls tonight.
Harry: Umm, I don't know.
John: Psst whatever go hang out with your G-friend then.