Green’s Dictionary of Slang

1. work that has been already paid for but is yet to be done; thus play for a dead horse, draw the dead horse, work for/off a dead horse, to perform such work.

1651		W. Cartwright Siedge in Plays & Poems (1951) 416: Now you’l wish I know, you ne’r might wear Foul Linnen more, never be lowzy agen, Nor ly Perdue with the fat sutler’s wife In the provoking Vertue of dead horse, Your dear delights, and rare Camp Pleasures .
1669		Nicker Nicked in Harleian Misc. II (1809) 108: Sir Humphry Foster had lost the greatest part of his estate, and then (playing, as it is said, for a dead horse) did, by happy fortune, recover it again.
c.1698		B.E. Dict. Canting Crew n.p.: To play or work for a dead horse for a trifle.
1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue n.p.: Dead horse. To work for the dead horse; to work for wages already paid.
1811		Lex. Balatronicum.
1822		R. Nares Gloss. (1888) I 227: †dead-horse. This term is applied now to work the wages of which have been paid before it is done.
1842		Ohio Democrat 27 Jan. 2/5: Work for a Dead Horse — There is a man [...] who has worked on average sixteen hours per diem for the last twenty years to pay notes which he had endorsed, and for which he had never received the value of one farthing.
1847		[A. Harris] (con. 1820s) Settlers & Convicts 327: In other cases it [i.e. leaving work unfinished ] is the consequence of a dishonest endeavour on the part of the labourer, after having largely overdrawn his account, to get rid of the debt; they call working out such a debt, riding the dead horse.
1848		Bartlett Dict. Americanisms 396: dead horse. Work for which one has been paid before it is performed. When a workman, on Saturday night, includes in his bill work not yet finished, he is said the following week to ‘work off a dead horse’.
1857		N&Q Ser. 2 IV 102: When he charges for more . . . work than he has really done . . . he has so much unprofitable work to get through in the ensuing week, which is called ‘dead horse’ .
1860		Hotten Dict. of Modern Sl. etc. (2nd edn) 128: ‘to draw the dead horse,’ dead-horse work. — working for wages already paid; also any thankless or unassisted service.
1862		E. de la Bédollière Londres et les Anglais 314/1: to work for the dead horse, [...] faire une besogne dont on a reçu le salaire par anticipation.
1873		Sl. Dict.
1885		Dly Eve. Bulletin (Mayseville, KY) 23 Nov. 1/3: They are piece-workers, finishing up what is called ‘dead-horse’ work, for which they have received their pay already.
1895		Crowe Aus. Sl. Dict. 23: Dead Horse, ‘working a dead horse,’ working on advanced wages.
1897		Herald (L.A.) 14 Apr. 10/2: The chief was asked if he did not think the punishment would be greater if the men were fined their pay and kept at work, in other words, make them work for ‘dead horse’.
1905		Bulletin (Sydney) 17 Aug. 33/2: Every shopkeeper is booming the Australian article, and the public now ask for them. One drapery firm, stuck with a large stock of English blankets, is working its dead-horse off as Australian. One to Australia! Rugs the same – the Marrickville people are making a slashing article.
1920		Burlington Wkly Free Press (VT) 12 Feb. 8/3: Cottagers working a dead horse, and clergymen recovering from their Sunday sermons [...] is it any wonder that Monday has an evil reputation?
1935		A.J. Pollock Und. Speaks 29/2: Dead horse, person working for nothing (usually liquidating a debt).
1958		H.E. Bates Darling Buds of May (1985) 75: Work it orf as dead horse.

2. (US/Aus./N.Z.) a debt that has been incurred by accepting an advance on one’s wages, it must now be worked off; thus ride the dead horse, work off the dead horse, bury the dead horse.

1832		E.C. Wines Two Years and a Half in the Navy i 73: (Note) Dead horses are debts due to the purser on account of advances of pay.
1848		Sth Aus. Register (Adelaide) 11 Nov./ 3/2: [T]he hardest and most disheartening of occupations, ‘working for a dead horse’ .
1877		Newcastle Morn. Herald (NSW) 11 May 2/6: That publican says [...] that he will be somethinged before he will ever again employ a drunkard to work off a grog score, or a dead horse, as the operation is popularly known in this district.
1891		Shields Dly Gaz. 28 Aug. 2/5: Sailors also consider that the first month at sea is work without remuneration, as they draw that amount of pay in advance [...] They call this working off the dead horse.
1895		Hawkes Bay Herald (N.Z.) 19 Aug. 2/7: That a man should be compelled to work off a ‘dead horse’ [...] is simply barbarous.
1898		E. Dyson Below and On Top 135: [A]s far as it was possible to judge, the ground would not pay for the working, let alone compensate for this gigantic ‘dead horse’.
1900–10		Stephens & O’Brien Materials for a Dict. of Aus. Sl. [unpub. ms.] 60: DEAD HORSE City and bush working to pay off old debts. When the earnings of one venture go to pay for losses in another venture either concurrent or past, the result is called ‘working dead horses.’ Paying doctors’ bills, back rent or borrowed money are cases in point.
1906		Poverty Bay Herald (N.Z.) 2 July 3/2: He had got into debt, and consequently ‘must turn to graft in order to work off as “dead horse”’.
1921		N.Z. Truth 29 Oct. 3/4: I could write an interesting article entitled ‘Working Off a Dead Horse’ only I know that nobody in New Zealand would read it once they found out that it wasn’t connected with betting.
1933		(ref. to 1890–1910) L.G.D. Acland Early Canterbury Runs (1951) 373: Dead horse, Working a – Working off an old debt, usually for overdrawn wages.
1944		P. Kendall Dict. Service Sl. n.p.: dead horse . . . advance pay for foreign peacetime duty.
1949		Dandenong Jrnl (Vic.) 21 Dec. 1/5: [heading] Still Working Off ‘A Dead Horse’! £258 A Week Goes In Interest & Redemption.
2003		McGill Reed Dict. of N.Z. Sl. 59: dead horse, to work off/bury a To pay a debt. Australian from mid-C19.

3. any form of debt.

1960, 1975

Wentworth & Flexner DAS 142/1: dead horse an unpaid debt for something that no longer exists.

4. any form of useless job, which doesn’t bring in any profits but still must be done; thus draw the dead horse, to work at such a job.

1860		see sense (1).
c.1905		J. Furphy Rigby’s Romance (1921) Ch. viii: 🌐 The foolishest bloke He could find to take on such a (adv.) dead-horse racket as gettin’ the Jews out o’ this perdicament.