A word upper-middle-class kids that are up their own arse use to say 'fuck off' or 'piss off' because they are too posh to swear. It is thought, by most cool enough people to be the single worst way to tell people to go away.
"Oh my gosh! Wasn't 'Casualty' good last night?"
"No, 'Casualty' is boring and poncey."