Green’s Dictionary of Slang

(Aus.) a general negative adj.

1946		Geraldton Guardian & Express 8 Aug. 6/1: He will be the unostentatious chief turning any ratbag ideas aside.
1949		Mirror (Perth) 13 Aug. 6/2: My sort’s rat-bag cobbers are turning on a shivoo sarvo.
1953		T.A.G. Hungerford Riverslake 116: You want to take a turn at it sometime [...] and battle with the ratbag kids and their mad mothers.
1965		W. Dick Bunch of Ratbags 262: Two blokes had been murdered by some of the real ratbag bodgies.
1974–5		B. Humphries Barry McKenzie [comic strip] in Complete Barry McKenzie (1988) 122: If mum’s ratbag enough to marry a chocolate-puncher, I’ll need a skinful to get em to the church.
1979		D. Maitland Breaking Out 200: Murphy, for all his ratbag ways, was one hell of a fair hand with the old brush.
1991		M.B. ‘Chopper’ Read Chopper From The Inside 123: The neo-Nazi and anti-Jewish ratbag groups are stronger than most people imagine.
1996		J. Byrell Lairs, Urgers & Coat-Tuggers 116: When it comes to idiocy and pure ratbag short-sightedness, Dan O’Brien even tops David ‘Yankee Aleck’ Davis.