noun noun, orig Austral 1: Rhyming slang for narknoun 1. (1898 —) . J.Alard Ya knows Bill, yer gettin' to be a real Noah's Ark (1968). 2:Austral Rhyming slang for 'shark'. Also Noah. (1945 —) . Bulletin (Sydney): 'I'll tell you what's worse than the Noahs,' said Edgar. 'What about those bloody dragon-flies?' (1982).