When you've done something so irresponsible that you get "grounded" for the foreseeable future. Applies to children by their parents, but equally applies to husbands by their wives.
Mike: "Can you come out tonight?"
Eric: "Can't I'm GFL"
Mike: "What now?"
Eric: "Not sure how long “for life” means. Maybe I'll get a release for good behavior."
Mike: "Wow. She's the judge, jury, and prosecutor."
Eric: "True Dat."
A:Damn she a goon. She like Plies.
B:Yeah she a GFL. She more of a goon than Plies. I thought she was Smartt but she can't speak right. She use that goon grammar