In 2019, "Sus" was just the scientific name for pigs, and maybe an infamous old English law.
In 2020, it meant suspicious, and was generally used in the context of "among us".
In 2021, it meant: relating to "Among Us" or resembling its stocky armless astronaut characters.
In 2022, it meant you were a little behind on meme culture.
In 2023, it basically just means that an act is perceived as stereotypically homosexual.
"I don't know man, you've been looking kinda sus lately"
2019 guy: *oink oink*
2020 guy: "Woah, you play it too?"
2021 guy: "DING DING DINGDING DING DING DING- DIDIDING"
2022 guy: "Bro that isn't funny anymore"
2023 guy: *silence* "YOU SAID YOU WOULDN'T TELL ANYONE!"