Green’s Dictionary of Slang

g.a.b.a. n.

[abbr. the great Australian bugger all]

(Aus.) the outback.

[UK]Guardian Weekly 22 Mar. [Internet] We fly over hundreds of miles of bush, scrubby gumtrees, dry paddocks, and salt flats. ‘That’s it, mate,’ says [the pilot]. ‘GABA – Great Australian Bugger All.’.
S. Winchester Pacific 376: What locals call the Gaba – the Great Australian Bugger-All.