Green’s Dictionary of Slang

(a) (US Und.) a sponger, a parasite on gamblers.

1854		Life in Boston & N.Y. (Boston, MA) 13 May n.p.: We would advise him to have his corners kept clear of gamblers, pimp and loafers [...] If you cannot keep the ‘rounders’ off any other way, why have them arrested.
1859		Matsell Vocabulum 116: rounder One who hangs around faro-banks, but does not play. In other words, a loafer, a man who travels on his shape, and is supported by a woman, but does not receive enough money to enable him to play faro. Gamblers call such men rounders, outsiders, loafers.
1867		Nat. Police Gaz. (NY) 23 Nov. 2/2: The professional gamblers [...] down to the ‘pickers-up’ and the ‘rounders’ number three hundred all told.

(b) (US) a rich, fashionable man-about-town, a playboy; occas. of a woman (see cites 1890, 1891).

1854		Congressional Globe 17 Jan. 1220: I have always found (President Franklin Pierce) a very kind and agreeable man — what the ‘rounders’ in New York would term a ‘glover’ [DA].
1866		Night Side of N.Y. 79: I doubt if there are many aware that Hash is known to all the rounders as ‘boned turkey,’ ‘corduroy’ and ‘West Broadway.’.
1879		Daly in J.F. Daly A. Daly 330: [We] are old ‘rounders’ and familiar with the voice, gait and peculiarities of most of the actors and actresses on the American stage [DA].
1881		Boston Globe 30 Aug. n.p.: A ‘rounder’ from Baltimore, who claimed to have ‘influence’ with the Maryland delegation, was paid five thousand dollars.
1890		Arizona Republic (AZ) 25 Aug. 1/5: These women are what those of their own set would describe as ‘sporty’ [...] their inclinations make them rounders, make them the best authority in the city on claims of various cafés as to excellence .
1891		Nat. Police Gaz. (NY) 14 Mar. 3/3: Davenport maintains that Cleopatra was a portly, physically powerful rounder who weut on rousing rackets with Antony for days and nights at a time.
1894		‘O. Henry’ ‘Tamales’ in Rolling Stones (1913) 248: Rounders at midnight, / Citizens solid, / Bankers and newsboys, / Bootblacks and preachers.
1906		‘O. Henry’ ‘Man About Town’ in Four Million (1915) 83: Why [...] a ‘Man About Town’ is something between a ‘rounder’ and a ‘clubman.’.
1913		H.A. Franck Zone Policeman 88 289: I came ostensibly as a ‘rounder’; it would perhaps have been advisable at the close of each evening’s entertainment to [...] announce: ‘Now, girls, I’m a dee-tective.’.
1922		Wash. Times (DC) 12 Nov. 32/6: This bird [...] You couldn’t get a dime from him with a pair of forceps and yet he claims to be a rounder.
1925		Wodehouse Carry on, Jeeves 7: I’d been told that in his youth Uncle Willoughby had been a bit of a rounder.
1930		Cab Calloway ‘Gotta Darn Good Reason Now (For Bein’ Good)’ 🎵 I was just a rounder turning nighttime into day.
1935		Z.N. Hurston Mules and Men (1995) 27: ‘Now,’ he said, ‘you rounders and brick-bats – yeah, you women, Ah’m talkin’ to you.’.
1942		W. Winchell On Broadway 3 Sept. [synd. col.] He is a middle-aged rounder, who came into Mr Billingsley’s menagerie with a girl he met only that evening.
1948		D. Dodge Bullets For The Bridegroom (1953) 34: Casey Jones was the rounder’s name.
1956		N. Algren Walk on the Wild Side 93: There were chippified blondes and elderly rounders, bummies and rummies and amateur martyrs.
1962		Ragen & Finston World’s Toughest Prison 816: rounder – A ‘good fellow,’ a free spender.
1975		J. Roe Same Old Grind 1: Hank, the McPhee Street rounder, was sitting in a bar in the Lido Club, having his first drink of the day .
1993		I.L. Allen City in Sl. (1995) 76: A particularly dissolute man about town has since the 1820s been called a rounder — a ‘swell’ rounder, if rich and fashionable. He was sometimes also qualified as an ‘all-night’ rounder, from his habit of ‘making the rounds,’ or seeking out all the sensual city’s ‘excitements’ and indulging his ‘artificial appetites,’ as they used to say.
2003		Gillian Welch ‘Wayside/Back in Time’ 🎵 Come all you good-time rounders, listening to my sound.

(c) (Can. prison) anyone familiar with the underworld.

1884		Fortnightly Rev. Mar. 389: A repeater before he was of age; a rounder, bruiser, and shoulder hitter [DA].
1899		J. Flynt Tramping with Tramps 80: The ‘scrappin’ gang’ no more appeals to them as a pastime or a source of happiness than it does to an old rounder.
1906		A.H. Lewis Confessions of a Detective 64: One I knew to be a tough Bowery rounder.
1933		Ersine Und. and Prison Sl.
1978		R. Caron Go-Boy! 209: Babear was a super sharp rounder who moved through the underworld like a jungle cat.

(d) (US) a pimp, a procurer.

1923

R. McAlmon Companion Volume 215: She [...] knew chorus men rounders, and one minister who was as queer as any moll in America.

(e) (US prison) a member of a prison gang, esp. of an Italian gang.

1992

Bentley & Corbett Prison Sl. 43: Rounder A mafia type gang member. Rounder is also used to mean any gangster type person.

(a) (US) a vagrant; cite 1896 refers to veteran sailors.

1891		J.A. Riis How the Other Half Lives 78: The old rounders can swing hand or foot in their sleep without betraying themselves.
1896		‘Frederick Benton Williams’ (H.E. Hamblen) On Many Seas 65: Old rounders some of them who had been on the coast since the year one, when Adam was ‘oakum’ boy in the Brooklyn navy yard.
1905		‘I Ain’t Bothered’ in J.F. Dobie Rainbow in Morning (1965) 166: I’m a nachel-born rounder and don’t need to work.
1915		Pittsburg Dly Post (PA) 20 Apr. 6/2: He describes himself as having been a ‘main stemmer’ (a tramp), a rounder, a barrelhouse bum and having traveled under the name of ‘Hoosier Slim’.
1925		Odum & Johnson Negro and His Songs (1964) 210: The term ‘rounder’ is applied not only to men, but to women also. In general the interpretation is that of a worthless and wandering person who prides himself on being idle. [Ibid.] 211: I didn’t give a nary red cent, fo’ she was no friend of mine. / Well, it’s one mo’ rounder gone.
1932		S. Brown ‘Call Boy’ in Botkin Folk-Say 250: Git up off o’ yo’ shirt-tails, / You dumb lazy rounders.

(b) (US Und.) a recidivist.

1909

I.L. Nascher Wretches of Povertyville 194: Most of them are rounders or ‘revolvers’ – that is, wretches who are repeatedly sent to the workhouse on the charge of drunk and disorderly.