Diff
Skill difference
Example
Clear QB diff in the Packers vs. Broncos game
Yeah, the outcome wasn't surprising

Related Slang
Skill issue | You're bad |
Git gud | Get good |
Fail | Failure |
Rekt | Wrecked |
Scrub | Loser |
Casual | Game that requires little skill |
Gosu | Highly skilled |
Most often, gamers use diff when trash-talking their opponents or teammates. For example, at the end of a League of Legends match, a losing player may enter "clear JG diff" in chat, to point out that their team's jungler was not as skilled as their opponents'.
While diff is most popular among League of Legends players, other gamers and even some non-gamers also use this slang term. For example, geeky TikTokers might use diff while describing the difference between two fictional characters' strength and prowess.