no good to gundy, phr. — Green’s Dictionary of Slang

no good to gundy phr.

[ety. unknown; ? the Welsh dial. gundy, to steal, thus ‘not worth stealing’; a relict of the great flood of 1852 that devastated Gundagai; a comment by an Aborigine, one Gundy, when rejecting a proffered drink of whisky; a rebuttal of a temperance preacher, attempting to force his views on the populace of Gundagai; note cit. 1945]

(Aus.) no good at all, definitely bad.

1906		Bulletin (Sydney) 19 Dec. 14/1: Re […] origin and meaning of […] ‘No good to gundy’. ‘Gundy’ is a corruption of a Welsh word meaning to steal, shake, pinch, or hook, and the expression simply means that a thing is not worth stealing.
1912		Bulletin (Sydney) 8 Aug. Red Page/4: Antonio no good to Gundy on first stretch.
1919		W.H. Downing Digger Dialects 35: no good to gundy — Of no advantage.
1924		(con. WWI) A.G. Pretty Gloss. Sl. [...] in the A.I.F. 1921–1924 (rev. t/s) n.p.: no good to gundy. Of no advantage, ‘no good to me.’.
1945		Baker Aus. Lang. 90: No good to Gundy, an elaboration of the simple ‘no good’, has been current since 1907 or before, and probably had its origin in America. There is a township in New South Wales named Gundy and attempts have been made to link the phrase with this place. The origin is more likely to be found, however, in the old U.S. phrase, according to Gunter. Gunter was a noted mathematician who gave his name to works of precision and accuracy.
1955		N. Pulliam I Travelled a Lonely Land (1957) 236/2: no good to gundy – absolutely worthless.
1968		S. Gore Holy Smoke 35: This is no good to gundy, they say.