Green’s Dictionary of Slang

1. anyone who refuses to pay their debts, gambling or otherwise.

1859		Era (London) 20 Mar. 3/3: The ‘welshers,’ those pests of the turf.
1864, 1867, 1870		Hotten Sl. Dict. 268: welcher a person who makes a bet without the remotest chance of being able to pay, and, losing it, absconds, or ‘makes himself scarce.’ In the betting ring a welcher is often very severely handled upon his swindling practices being discovered.
1868		Illus. Police News 27 June 4: [He] appeared [...] with a placard in front and behind him, on which, in large letters was inscribed ‘The Welcher of Sloane-street’.
1869		J. Greenwood Seven Curses of London 398: Does the reader know what is a ‘welsher’ — the creature against whose malpractices the sporting public are so emphatically warned? [...] A ‘welsher’ is a person who contracts a sporting debt without a reasonable prospect of paying it.
1870		Morn. Post (London) 15 Sept. 7/5: The inspector kicked him [i.e. the witness], called him a ‘welsher’.
1879		‘Autobiog. of a Thief’ Macmillan’s Mag. (London) XL 502: The following people used to go in there [i.e. an underworld public house] — toy-getters (watch-stealers), magsmen (confidence-trick men), men at the mace (sham loan offices), broadsmen (card-sharpers), peter-claimers (box-stealers), busters and screwsmen (burglars), snide-pitchers (utterers of false coin), men at the duff (passing false jewellery), welshers (turf-swindlers), and skittle sharps.
1882		Sydney Sl. Dict. (2 edn) 9: Welcher - A defrauding or decamping bookmaker [...] A person who makes a bet without the intention or ability to pay, and absconds.
1882		Nat. Police Gaz. (NY) 7 Oct. 7/1: The word ‘welsher ’ is defined in the slang dictionary as a person who makes a bet without the remotest chance of being able to pay, and losing it, absconds.
1884		Sporting Times 20 Sept. 2/3: The aristocrats are the veriest couple of welshers ever seen.
1885		Bulletin (Sydney) 18 July 18/3: A certain notorious English ‘welsher’ and ‘lumberer,’ known in police circles as Bill the Butcher, is a non-smoker and a sort of temperance apostle among his ruffianly friends.
1887		Sheffield Dly Teleg. 15 Sept. 5/4: [headline] Committal of a Welcher.
1890		‘’Arry’s Visit to the Moon’ in Punch Christmas Number in P. Marks (2006) 168: There was toffs [...] mixed up with the welcher.
1895		Truth (Sydney) 6 Jan. 6/1: A welsher named John Evans (a Welshman, by the way) was arrested at Randwick .
1895		Crowe Aus. Sl. Dict. 93: Welcher, a person who makes a bet without the notion of paying it, and accordingly absconds if be does not win.
1896		A. Morrison Child of the Jago (1982) 95: Those of the High Mob were the flourishing practitioners in burglary, the mag, the mace, and the broads, with an outer fringe of such dippers — such pickpockets — as could dress well, welshers and snidesmen.
1903		A. Binstead Pitcher in Paradise 190: The welsher who runs away with money can be punished for theft.
1904		Sun. Times (Perth) 17 Jan. 12/3: I got rooked by a couple of welshers.
1908		A. Stringer Under Groove 6: Dinny was never a welcher.
1910		Sun. Times (Perth) 6 Mar. 2nd sect. 10/6: The London Turf Guardian Society is an institution formed for the purpose of wiping out the welsher and exposing the backer who has no intention of paying if he loses.
1911		G. Bronson-Howard Enemy to Society 96: A favourite trick with welchers.
1914		W. Sickert New Age 19 Mar. 631: The painter is consumed with envy of the racecourse thief and the welsher.
1922		Joyce Ulysses 380: One time he would be a playactor, then a sutler or a welsher.
1924		G. Henderson Keys to Crookdom 413: Piker. [...] welcher. One who backs down on a bet.
1929		D.H. Clarke In the Reign of Rothstein 32: Why, every one would think I was a welsher if I quit now that I’ve got a few millions.
1932		(con. WWI) L. Mann Flesh in Armour 246: An artillery chap [...] looked least like a welcher.
1934		R. Sale ‘House of Kaa’ in Penzler Pulp Fiction (2007) 69: We can’t afford to have a welcher, Wilky. There’s too much money involved.
1938		D. Runyon ‘A Very Honorable Guy’ in Runyon on Broadway (1954) 429: Feet Samuels is nothing but a dirty welsher for not turning in his body to you as per agreement.
1944		J. Cary Horse’s Mouth (1948) 273: The batter-brained, cake-handed, wall-eyed welsher.
1957		H.S. Thompson letter 3 May in Proud Highway (1997) 53: That lowest and most odious of all humans – the welcher.
1959		M. Richler Apprenticeship of Duddy Kravitz (1964) 108: Max the Hack is no welsher.
1965		R.L. Pike Mute Witness (1997) 81: I never worry about anything, except maybe long-shots. And welchers, of course.
1966		J. Holledge Great Aust. Gamble 140: Technically he was not the welsher, but the bookie creditors had no doubt he was behind the ramp.
1977		Maledicta 1:2 138: Closer yet [is] the welsher, whose current sense, ‘one who defaults on a bet,’ was generalized from the earlier meaning of ‘dishonest bookmaker.’.
1999		G. Seal Lingo 147: a tug was a con man prepared to be violent and a welsher was one who took bets without any hope of covering them – then made himself scarce.
2012		J. Hodgkins ‘Peek-a-Boo’ in ThugLit Dec. [ebook] Sly’s boys always rode bicycles. It made it easy to chase welshers down.
2018		T. Pluck ‘Hot Rod Heart’ in Life During Wartime 96: ‘Kid here lost his pink slip [...] Now he’s welching’ [...] ‘Nobody likes a welcher, kid’.
2020		C. Hiaasen Squeeze Me 94: Being pegged as welshers would cost the sons [...] some valuable social points.
2024		J. Meades Empty Wigs (t/s) 909: What is chance of him being be welcher or abusive hitter?

2. in fig. use, one who disappoints, lets down.

1906

S. Ford Shorty McCabe 211: And me loafin’ back of the ropes with me hands in me pockets! I’d been a welcher, wouldn’t I?

3. an informer.

1924		G. Henderson Keys to Crookdom 419: Squealer – an informer [...] welcher.
1966		B. Reckord Skyvers Act II: jordan: You’ll go and nark, won’t ya! sylvia: Narker! adams: Welsher!
1994		P. Baker Blood Posse 246: He knew the punishment for welshers and dime-droppers.