SU (said 'S-U', not 'sue')stands for socially unacceptable. It is mainly used as an interjection or adjective to describe things that are socially unacceptable, weird, bizarre, or simply inappropriate in a give situation.
Did you just ask that complete stranger to rate your ass? S.U.!
That girl is such a freak. All I have for her are two words... S.U.
Derived from the abbreviation for “Student Union”, an S.U. is a smug, overprivileged young man from a middle class background who attended a private school before whatever costly further education he is currently in.
The sort of person Radio 1 wish their listeners were (rather than 40 year old forklift drivers), he will be studying a subject that is either ridiculously easy or meaningless, will never have had a job and will be financially reliant on his parents, whom he has already cost an astronomical amount.
Dressed in “Surf” fashions), these Prince Harry lookalikes (there are a disproportionate amount of pale ginger ones) blight cities bleating at the top of their lungs at their idiotic flatmates, buying pints of cider on their discount cards before sicking them up over halls of residence balconies.
At some point, borrowing Mum and Dad’s BMW just isn’t enough anymore and said parents will have to cough up for a “Gap Year” (despite the 20 or so he’s had already) wherever he’s heard there are prostitutes and weed. He will return from the trip to loudly tell everybody “What a real eye opener” the poverty he saw there was, despite there being districts not much better off a couple of miles from his parents’ £300,000 semi. In the unlikely event of finishing university, the S.U. will most likely take up work in Subway or Burger King but in some cases will swap his Che Guevara hoodie for a suit and go to work for an oil company or the government.
Geoff: "How did your gig go the other night, Jim?"
Jim: "Terrible. It was a student bar. Just a crowd of up their own arse S.U.'s!"