Green’s Dictionary of Slang

1. a housebreaker, a thief.

1823

‘Jon Bee’ Dict. of the Turf, the Ring, the Chase, etc. 88: The miller may adopt a stick or otherwise, as seems most convenient.

2. (UK Und.) a killer, a murderer.

c.1698		B.E. Dict. Canting Crew n.p.: Miller c. a Killer or Murderer.
1725		New Canting Dict. [as cit. c.1698].
1737, 1759, 1760, 1776		Bailey Universal Etym. Eng. Dict. [as cit. c.1698].
1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue.
1809		G. Andrewes Dict. Sl. and Cant.
1811		Lex. Balatronicum.

3. a vicious, intractable horse.

1825		C.M. Westmacott Eng. Spy I 177: eglan. (to the ostler) Well, Dick, what sort of a stud, hey? any thing rum, a ginger or a miller, three legs or five, got by Whirlwind out of a Skyscraper?
1876		‘Nimrod’ in Malet Annals of the Road 185: [W]ith rotten tackle, and bolting horses; jibbers, and millers [...] high blowers, and queer ones.

4. a boxer or prize-fighter, esp. one who relies on aggression rather than skill.

1810		‘A New Song Called The Mill’ in Holloway & Black II (1979) 251: Come all you jolly millers bold, / Whose hearts are cast of British mould.
1821		W.T. Moncrieff Tom and Jerry I iv: This what do you call it? – this cover-me-decently, was all very well at Hawthorn Hall, I daresay; but here, among the pinks in Rotten-row, the lady-birds in the Saloon, the angelics at Almack’s [...] even among the millers at the Fives, it would be taken for nothing less than the index of a complete flat.
1823		‘Jon Bee’ Dict. of the Turf, the Ring, the Chase, etc. 119: Millers – second-rate boxers, whose arms run round in rapid succession, not always falling very hard, or with determinate object.
1824		Pierce Egan’s Life in London 3 Oct. 5/3: Reed [is] one of the best little men on the list of millers.
1832		S. Warren Diary of a Late Physician in Works (1854) III 49: The Captain put himself instantly into attitude, and, being a first-rate miller [...] let fall a sudden shower of blows about Mr. Warninham’s head and breast.
1840		T. Hood ‘Miss Kilmansegg and Her Precious Leg’ in Poems (1846) I 171: Because she refused to go down to a mill / She didn’t know where but remembered still / That the miller’s name was Mendoza.
1842		Whip & Satirist of NY & Brooklyn (NY) 3 Sept. n.p.: This chef d’oeuvre of mills opened for those who love a mill and patronizes the millers.
1848		Flash Dict. in Sinks of London Laid Open.
1859		Matsell Vocabulum.
1895		C. Crowe Aus. Sl. Dict. 49: Miller, a fighter.

5. (Aus.) a cicada [the grinding of its legs].

1909		Queensland Times (Ipswich, Qld) 11 Nov. 7/7: The ‘floury miller’ or ‘floury baker’ is the best musician of them [...] this strange hush orchestra, and Christmas is upon us when we hear his voice.
1930		Australasian (Melbourne) 3 May 52/2: What a season this has been for the cicadas (commonly known as locusts)! Floury Millers, Greengrocers, Double Drummers, they have swarmed in their millions.
1940		Lithgow Mercury (NSW) 21 Aug. 6/3: There are about 150 species of the family of Cicadidae in Australia [...] the Red-eye and the Floury Miller are [...] well-known varieties.
1941		Baker Popular Dict. Aus. Sl. 46: Miller, a nickname for a cicada.