Sus can mean 3 things.
1: gay
2: sus is short for suspect or suspicious
3: okay
1: Bro, that bitch is sus.
2:Man that guy is lookin' a little sus
3: Mom says: George when you finish your homework take out the trash please.
George says: Sus
Sus means suspect or suspicious
Friend: I want to fuck that turtle
Me: WOW MAN THATS SUS!!
An example to say that someone in the hit game among us is suspicious