Commonly misunderstood as a term which stands for "Original Gangster," this versatile phrase (and it IS a phrase) actually means "Original Garvey," referring, of course, to Marcus Garvey- both the national hero of Jamaica and the founder of Pan-African activism later dubbed "Garveyism." The term "O.G." is used to describe a situation, object, or person who is slick, fortunate, above par, or of course, original. In essence, having resemblance or similarities to Garvey himself. (the Rastafarian Movement considers him a prophet)
Dead Prez: "This shit is O.G. This shit is O.G. Original Garvey Nigga!"
Dude #1: What happened to Kwaze-Murder after them jakes started shooting at'em?
Dude #2: nah. Kwaze straight-up pulled out the semi and blasted every which one of them lil' piglets.
Dude #1: That shit is O.G.