Green’s Dictionary of Slang

(Aus.) violence.

1983		Tharunka (Canberra) 20 Sept. 8/3: The lady behind the counter told me where I could stick my hardware. She was not user-friendly so I had to get stuck in with the biffo.
1991		R. Mossop Mooe That Roared 21: [T]he powers-that-be have sacrificed many of the features that made [rugby] league the greatest game of all – like biffo! My view that a face-to-face punch-up between two men is part and parcel of the game is well-known.
2001		T. Abbott in Aus. Hansard 28 Mar. 25864: It shows what Australian workers can do when they are free of the tyranny of the go-slow, the picket line and the biffo in the car park for anyone who does his own thing.
2010		Sydney Morn. Herald 18 Aug. 9/1: Is there something in Brisbane Water or is the biffo, evident around Gosford, the consequence of a passionate election campaign?
2017		T. Spicer Good Girl Stripped Bare 83: Returning to the [TV] station with a bit of biffo from the protest.