Green’s Dictionary of Slang

(US) goodbye.

1900		D. Belasco Madame Butterfly (1928) 15: Goon-bye, sayonara, Butterfly.
1930		J.P. McEvoy Hollywood Girl 202: Goom bi, slaves – see you in the factory tomorrow.
1943		R.L. Bellem ‘Dead Man’s Shakedown’ in Dan Turner Detective Mar. 🌐 ‘Goom-bye now.’ And I powdered before she could give me an argument.
1956		H. Gold Man Who Was Not With It (1965) 18: We’ll say goombye to the habit together, kid.
1965		F. Pollini Glover 178: Some target, man! [...] Hit it. Wahoom. Blokes, goomby, by the million. [Ibid.] 285: Toodooloo, goombye, that’s it then.
1976		N. Thornburg Cutter and Bone (2001) 199: ‘Gee thanks.’ ‘It’s nothing. Goomba for now.’.
2001		B. Jacques Lord Brocktree 87: Rogg and his family calling farewells. ‘Goombye.’.