Green’s Dictionary of Slang

fiddle n.3

[fiddle v.2 ]

1. a swindler, a card-sharp.

[UK]‘Ducange Anglicus’ Vulgar Tongue.
[UK]Sl. Dict.

2. (orig. US) a swindle, a fraud.

[UK]Sl. Dict. 160: Fiddle [...] In America, a swindle or an imposture.
[US]St. Vincent Troubridge ‘Some Notes on Rhyming Argot’ in AS XXI:1 Feb. 46: fiddle and flute or fiddle. A suit of clothes. [...] The word fiddle alone has its own slang meaning, especially as a verb, viz., to obtain by illicit means, generally including bribery or petty crime. Very near the American ‘graft.’.
[UK]F. Norman Fings II i: And ’e’s only pulling all the fiddles Cochran used ter swing!
[UK]R. Cook Crust on its Uppers 29: It served as a handy front when one was working the income tax fiddle.
[UK]A. Burgess Enderby Outside in Complete Enderby (2002) 297: It was a bit of a fiddle, and I think I’ve learned my leson now about that sort of thing.
[UK]G.F. Newman Sir, You Bastard 38: People [...] delighted in telling other people their little fiddles.
[UK]F. Taylor Auf Wiedersehen Pet Two 176: If the Customs and Excise found out about Ally’s fiddles, plus the rest.
[UK]N. Cohn Yes We have No 115: All that’s left is the fiddle.
[UK](con. 1950) M. McGrath Silvertown 197: The whole East End is a complex web of scams with the docks at its heart. New terms have to be invented for the art of the fiddle.
[Aus]S. Maloney Sucked In 41: ‘You want to know if the union was corrupt?’ ‘Was it?’ ‘There might’ve been the odd little fiddle’.

3. an unrewarding, annoying job of work.

[UK]Metro 3 Aug. 13: Say goodbye to the fiddle of taking off your nail polish.

In phrases

on the fiddle (also at the fiddle)

cheating, committing fraud, swindling.

[US](con. 1910–20s) D. Mackenzie Hell’s Kitchen 117: At the fiddle ... living dishonestly; trying to take advantage of.
[UK]J. Curtis You’re in the Racket, Too 9: Others, who had yet to raise the dough, were getting ready to go out on the fiddle.
[UK]P. Willmott Adolescent Boys of East London (1969) 148: The governor’s on the fiddle.
[UK]B.S. Johnson All Bull 209: The man before me had been cooking the wardroom wine accounts, not on the fiddle but because he did not know what he was doing.
[UK]R. Dahl Rhyme Stew (1990) 54: Hey diddle diddle / We’re all on the fiddle.
BBC Radio Listings 8 Aug. On the Fiddle Tue 8 Aug, 10:35 pm – 11:35 pm 60mins [...] With executive access to the biggest ever operation against organised benefit fraud [etc.].
[Aus]S. Maloney Sucked In 245: You reckon the bankbooks will make the cops think Charlie talbot and Barry Quinlan were on the fiddle.