Green’s Dictionary of Slang

(Aus.) very well, excellently.

1916		‘Anzac’ On Anzac Trail 34: Once in every three years or so, the rain came down good-oh, and washed half the houses away .
1920		C.H. Sayce Golden Buckles 120: The mills are working good-O .
1932		M. Marshall Travels of Tramp-Royal 85: I cooked a beezer of a breakfast, burning myself good-oh.
1949		L. Glassop Lucky Palmer 72: ‘Snow’s’ going extra well [...] He’s going good-oh.
1955		D. Niland Shiralee 33: They’ll go goodo with the cackleberries.
1966		P. Boyle At Night All Cats Are Grey 223: You stand facing each other with the clock ticking away goodoh.
1973		(con. 1930s) F. Huelin ‘Keep Moving’ 40: ‘You’re doing goodo, Fred,’ Jocka called from somewhere at the rear of the load.
1982		E. Mac Thomáis Janey Mack, Me Shirt is Black 134: He was swinging his cane stick goodo.
1983		J. Byrell (con. 1959) Up the Cross 70: After doing good-oh at dead horse Fearless Phyllis came up with [...] a trimmer of a notion.
1994		J. O’Connor Secret World of the Irish Male (1995) 86: Firin’ the free grub inteh themselves good-oh.
1997		C. McPherson The Weir 16: Patting himself on the back, goodo.
2005		P. Howard Curious Incident of the Dog in the Nightdress 56: Everything’s going goodo right now.