Green’s Dictionary of Slang

1. a highwayman; a robber.

1798		‘St Giles’s Greek’ Sporting Mag. Dec. XIII 164/1: The cull [...] remained at the bowsing ken, [...] till the flashmen had an opportunity of piking.
1801		G. Hangar Life, Adventures and Opinions II 60: Your flash-man, is following his occupation, scampering on his prancer upon the high tober.
1815		‘Some push along with Four in Hand’ Garland of New Songs (21) 2: Ya hip! had all the Brighton flashmen in a long trot.
1818		W. Perry London Guide 127: The glass circulates tro all round, including Flashmen, (thieves) with whom you are thus obliged to associate.
1823		(ref. to 1770) ‘Jon Bee’ Dict. of the Turf, the Ring, the Chase, etc. 80: The first flash men being highwaymen — that then greatly abounded (circa 1770).

2. a thug employed by a brothel to deal with undesirables and drunks.

c.1786		Grose Classical Dict. of the Vulgar Tongue ms. additions n.p.: Flash Man. A Bully to a Bawdy house.
1788, 1796		Grose Classical Dict. of the Vulgar Tongue (3rd edn) .

3. (also flash chap) a pimp.

1773		Harris’s List of Covent-Garden Ladies 102: She has a favourite man whom she supports [...] He may be stiled a proper flash-man.
1789		G. Parker Life’s Painter 150: A flash-man, a fellow that lives on the hackneyed prostitution of an unfortunate woman of the town.
1797		M. Leeson Memoirs (1995) II 130: When I first came into the parlour, I took you for some English flashman, such as ladies in London have about them.
1812		Vaux Vocab. of the Flash Lang. in McLachlan (1964) 241: flash-man: a favourite or fancy-man; but this term is generally applied to those dissolute characters upon the town, who subsist upon the liberality of unfortunate women; and who, in return, are generally at hand during their nocturnal perambulations, to protect them should any brawl occur, or should they be detected in robbing those whom they have picked up.
1821		Egan Life in London (1869) 313: Poll, in her eagerness to communicate this good luck to her flash man.
1833		‘Poor Dirty Bet’ in Lummy Chaunter 49: By her flash man she was turn’d up, / All her future sprees were furl’d up.
c.1833		[broadside ballad] My flashman has gone to sea [F&H].
1842		‘Sarah’s A Blowen’ in Nobby Songster 18: And see where the flashman, / Is sculking about, / For part of the swag, / He is on the look out.
1842		‘The Blowen And The Swell’ in Nobby Songster 43: That flash chap that you see there, is no man of mine.
1849		New South Wales, Past, Present, and Future I 14: This man was known to Mr. Day to be what is termed a flash-man; and, seeing his own imminent danger, he instantly spoke to him and called him a cowardly rascal, and offered to give him shot for shot, while he was re-loading [F&H].
1859		H. Kingsley Recollections of G. Hamlyn (1891) 26: ‘You’re playing a dangerous game, my flash man, whoever you are,’ said Lee.
1859		Matsell Vocabulum 33: flash-man A fellow that has no visible means of living, yet goes dressed in fine clothes, exhibiting a profusion of jewelry about his person.

4. anyone conversant with the criminal world and thus its vocabulary.

a.1790		‘The Flash Man of St. Giles’ in Farmer Musa Pedestris (1896) 74: I was a flash man of St. Giles, / And I fell in love with Nelly Stiles.
1816		T. Moore in Morn. Chron. 8 Feb. 3: I say, Hum, how fares it with Royalty now? / Is it up? is it prime? is it spooney — or how? / (The Bird had just taken a flash-man’s degree).
1819		T. Moore ‘The Milling Match’ in Farmer Musa Pedestris (1896) 85: Instant the ring was broke, and shouts and yells / From Trojan Flashmen and Sicilian Swells / Fill’d the wide heaven.
1828		High Life in London 3 Feb. 8/4: It was comical enough to see Langan [...] endeavouring to imitate the slang of Yorkshire, and Manchester, and London [...] He was the English flashman every inch.
1829		Sydney Gaz. 11 Apr. 3/3: I have been preyed upon by sharks, sharpers, flash-men, fencers, rum coves, squatters, nippers, lifters, and all the tag-rag-and-bobtail denoted by the worst words in the Slang Dictionary.
1840		Australasian Chron. Sydney) 25 Aug. 2/4: [T]he great body of the prisoners seemed to be completely under the thumb and tone of a few daring, reckless, and abandoned characters, who gloried in the appellation [...] of flash-men. No deed of villany, no degree of swearing, of impure and profane language, seemed bold or wicked enough for these miserable wretches.
1842		Morn. Post (London) 12 Feb. 6/3: A hypercritical flashman might even discover some anachronisms in the cant phrases put into the mouths of Jem Gabel, the Earl’s man of all-foul-work .

5. (US) a man-about-town, a loafer with no visible means of support but an endless appetite for good clothes, parties and places of entertainment; such a man lived by his wits and often off foolish women.

1823		Bell’s Life in London 16 Feb. 4/3: Luke Cox had seen lady Portsmouth and Mr. Alder walking together. His Lordship had said, ‘There goes my Lady and her Flash-man’.
1834		Marryat Peter Simple (1911) 252: A large mob was collected in the street, vowing vengeance on us for our treatment of their flash man.
1841		‘She Sleeps With A Tall Grenadier’ Gentleman’s Spicey Songster 23: What you have been out on the pave, / I now can see very clear; / And I’m told by an elderly dame, / That your flash man’s a tall granadier.
1857		Bell’s Life in Victoria (Melbourne) 3 Oct. 3/6: [A] pack of flash men, thimble-riggers, etc., have arrived to participate in the profits of to-day's grand Intercolonial match.
1870		Appleton’s Journal (N.Y.) 19 Feb. 212/2: They form the ‘Nineteenth-Street Gangs,’ the young burglars and murderers, the garroters and rioters, the thieves and flash-men, the ‘repeaters’ and ruffians, so well known to all who know this metropolis.
1903		Sydney Sportsman (Surry Hills, NSW) 7 Jan. 3/5: A flash man met a portly woman [...] As there was nothing to be m ade out of her her pointed to a well-known corner loafer of the well-dressed, never-work type [etc].

6. an intinerant hawker.

1862

S. Smiles Lives of the Engineers I Pt 5 i 307: Those articles were sold throughout the country by pedestrian hawkers, most of whom lived in the wild country called the flash, from a hamlet of that name situated between Buxton, Leek, and Macclesfield. Travelling about from fair to fair, and using a cant or slang dialect, they became generally known as flash-men [F&H].