Fromgin(“Australian aboriginal woman”) +piss(“inferior alcoholic beverage”).

• Audio(General Australian):

  (file)

gin'spiss (uncountable)

1. (Australia,slang) Poor quality beer.^[1]
   • 1998 September 29, AG, “A Winnah-Beck's Bier, Pretzels and Pinball!”, inrec.games.pinball‎^[1] (Usenet):

     As we Aussies would say a seppo beer like Coors tastes likegin's piss (you don't wanna know!) compared to ours - would you like some beer with your rocky mountain water!

   • 2002 October 28, tediboy, “Labatt Blue vs. Molson Canadian”, inalt.beer‎^[2] (Usenet):

     Both sound like some sort of Canadian/North Americangin's piss but I believe they are reasonable facsimiles of beer as we know it in the Antipodes, so I definitely would go the nearest.

   • 2004 July 25, Teotwawki, “Titles for Scurvy's Life Story”, inalt.music.deep-purple‎^[3] (Usenet):

     but he wears a nice hat tho, for whatever that's worth.
     a flagon of drunkengin′s piss p'raps ?

• pissings