git gud = get good,自带嘲讽要素,基本是说某人太菜了回去多练练
A intentionally misspelled phrase meaning "get good." Generally used to pock fun at and mock inexperienced players in a particular video game.
Person A: Damn it, I've died so many times and haven't even gotten my first kill yet.
Person B: Lol, git gud mate.