Green’s Dictionary of Slang

bombo n.1

[SE bomb + -o sfx (3); it ‘knocks one out’. Note SE bumbo, ‘A liquor composed of rum, sugar, water and nutmeg’ (OED)]

1. (Aus.) cheap wine, methylated spirits or a combination of the two.

[Aus]J.F. Dettman ‘The Removalists’ Here was Glory 63: I knew ’e liked th’ bombo – even then I got a shock, ’e / Not merely smelt uv plonk, ’e simply stunk!
[Aus]D. Stivens Courtship of Uncle Henry 25: Four of the pedos got drunk as owls one night bombo got it from the guards.
[Aus]Argus (Melbourne) 14 Oct. 5/4: ‘Plonk’ and ‘Bombo’ were deplorable names for Australian table wines.
[Aus]D. Hewett Bobbin Up (1961) 221: Old Plonko Charlie [...] went behind the bobbin boxes, where he kept his bottle of bombo.
[Aus]S. Gore Holy Smoke 26: He done in the whole issue on sheilas and bombo.
[Aus]B. Wannan Folklore of the Aus. Pub 124: Bombo: poor quality wine.
[Aus] (ref. to 1920s–30s) Hepworth & Hindle Boozing out in Melbourne Pubs 15: Those who followed the Bacchic way were variously known as plonk fiends [...] bombo bashers. [Ibid.] 16: The legendary drink of the twenties and thirties was the Fourpenny Dark. This was a stoup of nourishing bombo which, in the great days, was served in a mug with a handle on it.
[Aus]G. Seal Lingo 133: The problems associated with over-proof and downright dangerous concoctions are also numerous in colloquial speech: [...] red ned; bombo; chateau cardboard (all terms for poor quality wine).

2. see bumbo n.1

In compounds

bombo-basher (n.)

(Aus.) a (usu. street-level) alcoholic.

[Aus]Barrier Miner (Broken Hill, NSW) 23 Sept. 7/1: Many Sydney bombo-bashers are derelicts.
bombo joint (n.)

(Aus.) a shanty or public house that sells cheap wine and/or methylated spirits.

[Aus]Sun. Times (Perth) 28 Sept. 1s/1: Down and out for years, he spent most of his time around pubs and bombo joints.