A game term for an item or skill. It might also im some Manga, lightnovels and anime. It means superior Supreme Super Rare.
Player14728: I am the best I got a sr item.
Player69696: wel It seems you try to show me your weakness huh. As I got a sssr item.
Player14128: get a girlfriend weeb
Player69696: wel stop being a simp karen
Used in csgo, shitty Russian (other s in this word stand for cccp parody)
Mad Russian : Rush Berlin, cyka blyat
Mad Others (e.g. German) : you MF SSSR