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.

[Aus]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.
[Aus]C.W. Chandler Darkest Adelaide 8/2: ‘You see, his tart is too young at the game. She’s a charity tart— gives tick, you know. That's no good to Gundy’.
[Aus]Bulletin (Sydney) 8 Aug. Red Page/4: Antonio no good to Gundy on first stretch.
[Aus]W.H. Downing Digger Dialects 35: no good to gundy — Of no advantage.
[Aus](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.’.
[Aus]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.
[Aus]N. Pulliam I Travelled a Lonely Land (1957) 236/2: no good to gundy – absolutely worthless.
[Aus]S. Gore Holy Smoke 35: This is no good to gundy, they say.

In phrases

good enough for gundy

(Aus.) reasonably good, acceptable, not too bad.

[Aus]Scone Advocate (NSW) 23 Apr. 2/7: Such [people] will tell us that this is only a little unimportant country village. It is only Gundy and anything is good enough for Gundy. But any thing is not ‘good enough’ for Gundy. The expression, ‘good enough’ is detestable. It is the argument and excuse of the shiftless, the indolent or the incompetent.
[Aus]Sydney Sportsman (Surry Hills, NSW) 2 Sept. 5/1: Our displays [of baseball] are good enough for Gundy.
[Aus]Aus. Worker (Sydney) 7 Jan. 12/5: And when the little beauty lays / Each day, including Sunday; / Yes, poultry-breeding wins our praise / It’s good enough for Gundy.