"Sus" traces back to 1920s police and criminal slang in the UK and US (such as the British "sus law," which allowed police to stop and search anyone deemed suspicious).
Before its mainstream explosion, "sus" was actively used in African American Vernacular English (AAVE) and youth communities throughout the 1990s and 2000s.
The term blew up in 2020 via the game Among Us, where players regularly accused others of acting "sus" while trying to identify the secret impostor.
Also, used to call out "feminine" ways in men, "masculine" mannerisms in women.
