G.C. are the initials for Gaming Car. If you acquire this name you cannot be compared to. You are the greatest of all time. You make even the worst things good, you are awesome.
G.C.F stands for Golden Closet Films, they're basically short vlogs, filmed, produced, and edited by the amazing Golden Maknae, Jeon Jungkook of BTS. They basically consist of various shots of BTS in foreign countries, you'll notice some of the members here and there, the G.C.Fs always show the beauty of the scenery and focus on the spectacular views of the landscape.
Your friend: Did you watch Jungkook's latest G.C.F?
You: The GCF in Tokyo? Yes, I did!
Your friend: It was a work of art!
This is an abbreviation for "grandpa cock connoisseur". This refers to someone (usually female) who prefers the penis of older men, potentially elderly and senile. This girl is in her early twenties and has had a series of daddy issues she is trying to solve by sleeping with men her dads age.
Dude 1: "dude what's with maggie?"
Dude 2: "IDK man, she's a major G.C.C."
Dude 1: "a what?"
Dude 2: "a Grandpa Cock Connoisseur"
Dude 1: "oh yeah, she totally likes old wiener"