Green’s Dictionary of Slang

1. a racecourse swindler; thus blackleggism, swindling, black-legged adj.

1771		P. Parsons Newmarket II 163: The frequenters of the Turf, and numberless words of theirs are exotics everywhere else; then how should we have been told of blacklegs, and of town-tops?
1781		G. Parker View of Society II 168: Levanters. These are of the order and number of Black Legs, who live by the Broads and the Turf.
1797		P. Colquhoun Police of the Metropolis 141: Sharpers and blacklegs find an easy introduction into the houses of persons of fashion [...] for the purpose of playing at those most odious and detestable games of hazard.
1802		Sporting Mag. July XX 188/1: Elegant gentlemen without character—black legs—sharpers of every denomination.
1812		W. Combe Doctor Syntax, Picturesque (1868) 34/2: The crowd with their commission pleas’d / Rudely the trembling Black-leg seiz’d.
1828		Lytton Pelham III 310: Gentlemen, as he called them, but whom I have since found to be markers, sharpers, and black-legs.
1833		Ely’s Hawk & Buzzard (NY) Sept. 21 n.p.: [N]or shall we meddle ourselves with sporting gentlemen, black legs or their stool pigeons .
1835		G. Kent Modern Flash Dict. 6: Black-legs – sharpers, fellows who lay wagers, and after losing cannot pay them; a professed gambler.
1840		R.B. Peake Devil In London III iii: You have been deeply wronged by this blackleg. Your horse was hocussed.
1841		Australasian Chron. (Sydney) 15 June 2/2: [W]hat a gulf there must be fixed between the gentlemanly flat and the genteel blackleg.
1850		Morn. Chron. (London) 12 Apr. 6/3: [T]he old dicer [...] fell a martyr to that ‘blackleggism’ of which he so long had been recognised as the [...] patriarchal chief.
1854		N.Y. Clipper 7 Jan. 3/2: There are certainly disreputable characters called sporting men ; but does it necessarily follow that the whole fraternity are [...] as a certain lawyer styles them, blacklegs?
1854		F. Smedley Harry Coverdale’s Courtship 366: He is [...] half-jockey, half-dealer, and whole blackleg of a low stamp – there are hundreds such on the turf.
1860		Carlisle Wkly Herald (PA) 2 May 2/1: The whole tribe of professional shoulder-hitters [...] and blacklegs.
1860		R.S. Surtees Plain or Ringlets? (1926) 57: The great spread of black-leg-ism making it impossible to buy all backbiters off, Johnny adopted the anti-turf, anti-betting tone.
1861		(con. 1840s–50s) H. Mayhew London Labour and London Poor I 444/2: ‘The eye-glasses,’ said a man who vended them, ‘is sold to what I calls counter-hoppers and black-legs. You’ll see most of the young swells that’s mixed up with gaming concerns at races.
1873		Western Times 25 Dec. 2/5: Black boots, black looks, black legs.
1877		[J.S. James] Vagabond Papers 2nd ser. 128: [O]utlawed black-legs, men who subsist by getting up sham ‘sweeps,’ or laying against ‘dead ’uns’.
1879		Nat. Police Gaz. (NY) 22 Nov. 7/1: A well-known concert saloon visited by the very lowest gamblers, thieves and blacklegs.
1882		Sydney Sl. Dict. (2 edn) 1: Black Legs - Those who bet and evade paying their losses.
1884		H. Smart Post to Finish I 4: About as evil a specimen of gentleman blackleg as it was possible to encounter.
1890		G.W. Walling Recollections 52: His funeral [...] was attended by ‘toughs,’ ‘blacklegs,’ gamblers, and ‘sports’ of all grades.
1894		G. Boothby On the Wallaby 254: The racing code is lax [...] we met men who made it their sole business [...] to tramp the bush with a likely animal, practically living on what he earned them, either by winning, or what is technically termed, ‘running stiff.’ These men are called Forties, otherwise Spielers or Blacklegs.
1900–10		Stephens & O’Brien Materials for a Dict. of Aus. Sl. [unpub. ms.] 99: Monte-man: applied to professional card or gambling swindlers as a class. Synonyms: spieler, blackleg, takedown, magsmen.
1907		Sun. Times (Perth) 28 Apr. 1/1: The Pinjarra blackleg has crawled himself out of being shifted to Waroona.
1949		Monteleone Criminal Sl. (rev. edn).
1999		G. Seal Lingo 147: Those found to be consistent swindlers were known as blacklegs and were warned off the course.

2. (also blacklegs, blackshanks) any swindler; thus blacklegging, black-leggery, swindling.

1770		Town & Country Mag. Dec. 654/2: Had it not been for this accident, it [i.e. a purse] would have been by this time dispersed among the black legs and thieves of Newmarket.
1793		F. Reynolds How to Grow Rich II i: I’m an old rook and a black legs!
1794		Sporting Mag. Oct. V 49/1: It has since become a proverb among Russian blacklegs, that such a one plays like a midshipman, if fortune favours him a little too much.
1800		Sporting Mag. Sept. XVI 275/2: Mr. F—, the Barrister, had lately occasion to cane a black-leg at a coffee house near the Temple.
1815		Commercial Advertiser (N.Y.) 24 Mar. 2/4–5: [headline] The Black Legs and the Patent Swindling Bag [...] We have heard of many patents [...], but this is the first time we have heard of a patent for an improvement in the art of swindling.
1818		W. Perry London Guide 61: They [i.e. cheating casinos] were antecedently known only to a few (the chosen few) black legs.
1822		‘Life in London’ in C. Hindley James Catnach (1878) 126: Where blacklegs and sharps often gammon the flats.
1832		Egan Bk of Sports 170: Black-legs are not the peculiar growth of our [boxing] ring. Wherever men will sport on chance events, there Mr. Blackshanks will be found walking.
1834		D. Crockett Exploits and Adventures (1934) 167: When we returned to the deck the blackleg set to work with his thimbles again. [Ibid.] 170: He now commenced professional blackleg on his own hook.
1841		Punch 31 July I l I 26: Took up a couple of young black-legs, whom I detected playing at chuck-farthing on Saffron-hill.
1848		‘Ned Buntline’ Mysteries and Miseries of N.Y. IV 87: His honor – the honor of a professional blackleg!
1853		R.S. Surtees Mr Sponge’s Sporting Tour 359: Believe he's nothing but a great poaching blackleg.
1855		Delhi Sketch Bk 1 Jan. 9/1: [He] was neither a rake nor a blackleg, but a thoroughly honest kind hearted chivalrous fellow.
c.1858		J.H. Green Reformed Gambler 162: ‘It is a desperate case, indeed, boys,’ says Capt. Howard, as he addressed the five blacklegs, in a state-room where he had summoned them for the purpose.
1858		Sth Aus. Register (Adelaide, SA) 21 Sept. 3/5: Legal Definition of a Blackleg [...] The Lord Chief Baron [...] said that ‘the word “blackleg” has been used long enough in writing and speaking’.
1861		Hills & Plains I 108: Budlee was considered a notorious blackleg.
1864		Reynolds’s Newspaper (London) 29 May 4/3: [A] man with the tastes of a pig, the brains of a baboon and the morals of a blackleg, may be a member of parliament.
1870		W.W. Fowler Ten Years In Wall Street 35: The puritan and blackleg exhange a sympathetic smile, when they see the stocks advancing in which they are interested.
1885		Bulletin (Sydney) 24 Oct. 5/2: The place is full of money, fools to spend it, and blacklegs to get it.
1887		Alpena Wkly Argus (MI) 14 Dec. 4/5: Seth had dound the elephant, but he did not know it [...] He had fallen in with [...] three black-legs of the most unscrupulous [...] character.
1892		H. Nisbet Bushranger’s Sweetheart 9: Debts of honour, which [...] would leave me branded as a blackleg amongst all the fellows I knew.
1900		Marvel 22 May 10: An entrance was to be effected [...] and the whole nest of blacklegs smoked out.
1903		J. Furphy Such is Life 33: He is an unknown and elusive quantity, merging insensibly into saint or scoundrel, sage or fool, man or blackleg.
1912		E. Pugh City Of The World 266: It’s the first dodge the blackleg ’as got to learn if he wants to do any good at the game.
1922		Yorkville Enquirer (SC) 29 Dec. 4/1: The sympathizers with the Ku Klux are denouncing the other side as boot leggers and black legs.
1935		A.J. Pollock Und. Speaks n.p.: Black-leg, a thieving stock salesman who associates with wealthy people.

3. a professional gambler or layer of odds.

1776		G. Colman Spleen I i: I would fain have been among the red ribbands and black legs at Hell in the evening, and tried my luck with tossing the cubes about.
1848		Bartlett Dict. Americanisms.
1850		G.G. Foster Clelio 101: A kind of hybrid betwen the b’hoy and the blackleg.
1866		Night Side of N.Y. 18: Individuals who patronize faro banks [...] clerks and blacklegs, Fulton market butchers and navy officers.
1873		J. O’Connor Wanderings of a Vagabond 50: He was the first professional sport, gambler, leg or black-leg, all of which terms are synonymous, of whose acquaintance I had the honor.
1874		Mix & Mackeever N.Y. Tombs n.p.: [of gambler Billy Mulligan] A professional blackleg [...] as desperate a character as could be found among the rowdy element of New York.
1882		‘Paris Inside Out’ in Nat. Police Gaz. (NY) 30 6/2: ‘If you ask a man to take a hand you are looked upon as a card sharper, a black leg, just as if the world contained nothing but cheats and blackguards’.
1940		H. Asbury Gangs of Chicago (2002) 35: Resolutions adopted by this committee pledged its members to [...] wage unrelenting warfare upon sharpers and blacklegs.

4. a confidence trickster, typically preying on visitors to a city.

1838		‘Paul Pry’ Oddities of London Life I 156: [In Piccadilly] I was accosted by a stranger, who advised me to be very careful I was not picked up by some of the blacklegs who were prowling about. I retorted he was a blackleg for his trouble.
1844		J.W. Kaye Peregrine Pultuney I 209: ‘The long scoundrel deserves to be kicked out of the ship as a sharper and a black leg, which he is’.

5. (US Und.) a professional criminal.

1930		J. Lait Put on the Spot 109: Secretary Gleason called a council of his blacklegs in the foul, smelly cellar of one of the gang’s cutting plants.
1952		C. Hamilton Men of the Und. 320: Blackleg, A professional criminal.
1960		(con. 1950-1960) R.A. Freeman Dict. Inmate Sl. (Walla Walla, WA) 11: Black leg – a professional criminal.