Country Dictionary

You're probably here from cinimodde's "December 19 1999" definition. There's no "o.g" here made by a bob in 1999. I checked all 70 pages, man.

Person 1: Man, I heard that there was a rare 1999 definition called "o.g" made by bob on December 19th, 1999.
Person 2: Nope, that's a myth. But maybe one day, we will truly find a 1999 definition. The search continues.
Person 1: Aw man. That sucks ass.
Person 3: Hey guys, I found a "1999" definition!1!
Person 1 and 2: SHUT THE FUCK UP

Original gangster or old guy depends on the context

He's a O.G: noun eg old guy :2) noun; he's a old gangster

original glue-sniffer

Lyric in a Beck song, 'In A Cold Ass Fashion'
"O.G.-- original glue-sniffer"

A group chat where one person always overreacts

OMG GUYS GUESS WHAT
what?
what?????
MY LIPBALM RAN OUT

Therefore the group chat is named O.G plastics