The full form of OG is original gangster
“OG” stands for “original gangster”.
It is a phrase that is often used in rap and hip hop culture. This later found its way into the internet and texting culture. The long form of “OG” is “original gangster.” The meaning of “original gangster” is someone who is from “the old school” or someone who has a depth of knowledge or experience. If new gangsters think they are tough, then “OGs” are many times tougher.

The term “original gangster” is said to have come about in the 1970s. During this time, a Los Angeles street gang known as the crips was quickly expanding. Those who were called “OG” were some of the founding, or “original,” members. As a result, they were called the “original gangsters” or “OGs.”

Conversation Examples
Let’s take a look at some examples in action.

Example 1:
Gamer 1: No matter how much I play, I never get any better.
Gamer 2: Have you tried talking with NightStalk3r? He’s an OG on this game.