In Australia, it is a derogatory word denoting a person who saps all the fun out of any given situation. Derived from the temperance movement in Australia and New Zealand at the turn of the C20th, when it was hurled as an accusation towards
conservative teetotallers who were too prim and proper to relax and socialise, it has become a more generic term that can be assigned to any straight bore lacking a
sense of humour, especially petty bureaucrats and Aussies
politicians.
Cool chick: Coming to
the party?
Nerd: No, I have to write an essay for uni.
Cool chick: C'mon, ya wowser! Forget the essay and let's party, mate.
Nerd, slowly de-nerdifying: Y'know,
you're right. Let me at that party. Verily.