Origin of wowserPossibly from dialectal wow, to howl, complain, of imitative origin.
From UK dialect. In the pro-temperance sense, Australian from early 1900s.
John Norton, an early enemy of wowsers (temperance sense), claimed it to be an acronym for "We Only Want Social Evils Remedied", but that is likely a folk etymology.
A story has it that gospellers in the streets of Clunes, Victoria in the 1870s were called rousers but one of the town councillors had a speech impediment and couldn't pronounce his "R"s, thus giving wowser. (Reference: Bill Wannan, Australian Folklore, Lansdowne Press, 1970, reprint 1979 ISBN 0-7018-1309-1, under "Wowser", page 568.)