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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!"
by UpYourKilt August 28, 2011
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A german/french swear word directed specifically at people. Placed either in front or behind name of person.
example: austin su!
similiar in meaning to bodoh and f
stumme Scheiße jolere su.
lare su la merde sourde-muette disparaissent et meurent
by restim August 20, 2005
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a nest.. or vinegar
"su..."
"su? *places nest on head*"
"*shake head*...su"
"* give giant bottle of vinegar*su..?"
"*nod.. and chug entire amount*"
by Scott " the yellow dart " Hoey December 02, 2003
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A child-like person who performs many immature acts. This person is also the epitome of lame.
You are such a lame person, like "Su"
by Joer January 24, 2007
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Someone or something boring (usually used in French slang)
David liberato est trop su
by Faranakmtl April 28, 2019
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A shortened version of the word suicidal. It is used as an exaggeration, not to be taken serious. Usually the word will be used as a complete overreaction to what actually happened.
"Im su the Cowboys lost."

"Im su I didn't get french fries with my burger."

"Im so su about going out to eat with him tonight"
by MAdams1 August 12, 2011
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It means when a person wants you to Shut Up but it's abbreviated because they don't want to hear you
Guy 1:hey hey hey(in text)
Guy 2:SU(in text)
Guy 1:ok fine !!(on text)
by Prretierindiviual December 27, 2019
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