Green’s Dictionary of Slang

1. a swindler.

1811		Lex. Balatronicum n.p.: Tell the macers to mind their fakements; desire the swindlers to be careful not to forge another person’s signature.
1828		G. Smeeton Doings in London 39: It is a game in very great vogue among the macers, who congregate nightly at the flash-houses.
1832		Public Ledger 12 Nov. 3/3: Swindlers of every description, among which are Macers, duffers, and ring-droppers.
1840		London Mag. Feb. 56: To the sword must yield powder-wigged penmen, / And one macer’s match for e’en TEN-MEN.
1851		Bell’s New Wkly Messenger 9 Mar. 6/2: The several descriptions of London thieves are [...] macers, or those who write begging letters.
1860		R. Nicholson Rogue’s Progress (1966) 157: Kearney hath a macer’s eye / He sees the die before it’s landed.
1873		Sl. Dict. 220: Maceman, or macer a welcher, magsman, or general swindler; a ‘street-mugger’.
1882		Sydney Sl. Dict. (2 edn) 6: Macer - A sponger, swindler, gambling rogue.
1886		Sporting Times 22 May 3/3: The macer, who is probbaly a connoiseur, ventures the opinion that they [i.e. ‘off’ whelks] are ‘sanguinary lofty’.
1887		Ft Worth Dly Gaz. (TX) 29 Aug. 6/4: No gillie can do me, and that duck’s a macer sure’s you’re born.
1890		‘Doss Chiderdoss’ ‘Unexpected Places’ Sporting Times 8 Mar. 1/3: He was ducked with sundry others, fellow macers, men, and brothers.
1915		Lincoln (NE) Daily News 2 Aug. 3-A: Many a good tap would come acrost f’r de macer if he wasn’t gittin’ maced so of’n by zobs dat he knows, dressed-up rummies, dat sink de pick into him ev’ry time he goes out t’ take de air.
1977		D. Powis Signs of Crime 192: Macer [...] cheat.

2. a thief, a villain.

1883		G.A. Sala in Illus. London News 28 April, 407, col. 2: The lovely and loving spouse of an abandoned macer, [...] to further whose villainous ends she consents to ‘nobble’ Damozel in his stable [F&H].
1977		D. Powis Signs of Crime 192: Macer Thief.