Malcolm Turnbull, who has spent much of this week defending government secrecy over his phone conversation with Donald Trump, has just been done a favour by the forces of media scrutiny and public accountability.The (unlinkable) OED says the slang word means to swindle, and traces it back to 1928:
On the surface, this is just another SNAFU - another uncontrolled leak that has gazumped the Prime Minister's agenda, right when he wants to talk about tax cuts, cheaper electricity, and affordable childcare.
1928 Daily Express 19 Dec. 2/7 ‘Gazoomphing the sarker’ is a method of parting a rich man from his money. An article is auctioned over and over again, and the money bid each time is added to it.The spelling "gazump" arrives in 1971, and there's also "gasumph," "gezumph."
But wait, here's a blog post by that goes into much more detail: "Gazip, Gazipe, Gazump - Variants of Gazabo?" It looks at an earlier American word, "gazump," from 1910, that referred to an old automobile.