> I don't really get what Brits mean by "cunt."
Speaking for England:
It's a person of absolutely no redeeming features, also wilfully malicious, petty, cruel and generally vile. Someone (possibly Anthony Burgess?) once lamented the lack of an English equivalent of Persian "drwg" - "a thoroughly and unredeemably bad sort": that would be the c-word.
I'd claim that "cunt" in BritEng has two distinct senses, these two senses being only historically connected - in particular it is applied mostly to men and has no associations of effeminacy. The "vile person" sense is much the more widely used.
It's probably used most by working class men; but the Jarvis Cocker usage isn't class motivated, as the word is really about what they used to call moral character.
John