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.