Basically, German word for shit. Many uses. Also used as 'fucking (something)'
Mein scheiss computer ist im arsch. (My fucking computer is fucked up in the ass).
So 'ne Scheisse! (that's fucked up!)
Dieser scheiss typ hat mich nicht angerufen. (This fucking guy didn't call me)
Ask the nasty lunch lady what's for lunch, and she could say: "Scheisse mit Reis" (shit on rice)