Definitions by Owen42069

gmg 

It means "grind(s) my gears" which is an alternative expression for "pmo" (piss(es) me off).
It was invented on the social media platform Instagram and is used as a replacement for pmo because pmo got used too often.

He: I like school.
Me: You gmg bro.

gmg by Owen42069 April 22, 2025