Green’s Dictionary of Slang

to steal, to rob, to deceive; thus gonnofing or gonophin, stealing, deception.

1857		Dickens ‘The Detective Police’ in Reprinted Pieces (1899) 143: From the swell mob, we diverge to the kindred topics of cracksmen, fences... designing young people who go out gonophing, and other ‘schools’.
1865		Leaves from Diary of Celebrated Burglar 93/1: There they used to talk over ‘gonnoffing,’ plan robberies, ‘fence their swag,’ leave their ‘tools,’ &c.
1873		Sl. Dict. 184: A gun’s practice is known as gunoving.
1886		Sporting Times 22 May 3/4: ‘Them Phillipses was always a gonophin’ lot [...] Old Abe Phillips once gave a blind man a French halfpenny an’ sneaked his dog’.
1890		‘Morris the Mohel’ ‘Houndsditch Day by Day’ in Sporting Times 15 Feb. 2/2: Ve bowled Aaron Motzaberger out in a peautiful piece o’ gonophin the other day.
1893		P.H. Emerson Signor Lippo 104: What’s he been up to? Gonnofing?
1900		Sydney Sportsman (Surry Hills, NSW) 3 Oct. 1/2: Three twopenny stamps that were on the table could not be found after Sol had left, and it’s 10 to one that he gonnoffed them.
1914		Jackson & Hellyer Vocab. Criminal Sl. 38: gonif [...] to rob.
2004		J. Ellroy ‘Hot-Prowl Rape-O’ in Destination: Morgue! (2004) 309: We gonifed a golf cart and coursed out on the course.