Green’s Dictionary of Slang

1. a farthing; also in fig, sense, someone/something worthless.

1639		J. Taylor Crabtree Lectures 47: Most sure my father was frantick [...] to match me to such a Mopus.
1661		‘Peter Aretine’ Strange Newes 5: Wand. Wh— . Though my husband be a mere Mopus to a man of mettle, yet my Gusmond is a man able to defend me.
c.1698		B.E. Dict. Canting Crew n.p.: Mopus c. a [...] Farthing.
1725		New Canting Dict. [as cit. c.1698].
1737, 1759, 1760, 1776		Bailey Universal Etym. Eng. Dict. [as cit. c.1698].
a.1790		H.T. Potter New Dict. Cant (1795).

2. a halfpenny.

c.1698		B.E. Dict. Canting Crew n.p.: Mopus c. a half Penny.
1725		New Canting Dict. [as cit. c.1698].
1737, 1759, 1760, 1776		Bailey Universal Etym. Eng. Dict. [as cit. c.1698].
a.1790		H.T. Potter New Dict. Cant (1795).
1809		G. Andrewes Dict. Sl. and Cant.
1810		‘Clown’s Peep into the Seraglio’ in Batchelar’s Jovial Fellows Collection of Songs 3: In Turkey heads and tails depend all on the toss up of a ha’penny; and when the Sultan wants the mopusses, he orders them to strangle the first bashaw they can catch.
1841		‘Bon Gaultier’ ‘My Mother’ in Farmer Musa Pedestris (1896) 131: Who’d [...] / slily to my fob repair / And leave me not a mopus there?
1857		S.F. Call 26 Mar. n.p.: [He] Went to fight the furious tiger, / Went to fight the beast at faro, / And was cleaned out so completely / That he lost his every mopus.

3. usu. in pl., money in general.

1779		Nocturnal Revels 2 217: A Masquerade [...] that he could no more refrain from (if the Mopus’s, as he called them, were aboard) than he could refrain from the Burgundy and Champaign.
1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue n.p.: Mopuses, the mopusses, money.
1793		J. O’Keeffe London Hermit (1794) 9: So you’ve picked up the mocusses [sic] in the Indies [...] Never look’d after me.
1796		T. Morton Way to Get Married in Inchbold (1808) XXV 25: What! dizen’d out – expect to touch the mopusses, eh?
1811		Lex. Balatronicum [as cit. 1785].
1824		Egan Boxiana IV 443: Ned not having the mopusses to spare.
1826		N.-Y. Enquirer 20 July 2/1: [Jacob Barker is ‘alive and well’, bustling about Wall-street during this crisis] . . . ’tis [said] that Jacob has touched the mopusses, has held his [...] out in the shower of gold.
1833		‘The Chummies’ Society’ in Fun Alive O! 53: And I thinks them ’ere chaps very low / What goes cadging about for the mopusses.
1833		Ely’s Hawk & Buzzard (NY) Sept. 7 n.p.: Jack Slowey hasn’t plank’d the mopusses, wants touching up for a cool $5 .
1840		R.B. Peake Devil In London I iii: My lord wants her mopusses to patch up his own ragged estate.
1845		Bell’s Life in Sydney 27 Dec. 1/5: The mopusses are coming into tho squatters exchequer, from the proceeds of their present clip.
1850		‘Ned Buntline’ G’hals of N.Y. 134: It’ll jes’ be when you shell back the mopuses that yer emptied my pockets of!
1855		Cornwall Chron. (Launceston, Tas.) 19 Dec. 5/3: To be gibed by a mob of police [...] who thought I was ‘good for mopusses,’ as they termed it when they first accosted me [etc] .
1863		‘Paddy’s Chapter on Pockets’ in Donnybrook-Fair Comic Songster 26: With pocket in hand, and the mopusses in it.
1865		R.S. Surtees Facey Romford’s Hounds 390: He has made mopusses enuff to come back quite indiapendent [sic].
1873		Sl. Dict. 229: Mopusses money; ‘MOPUSSES ran taper,’ money ran short.
1882		Sydney Sl. Dict. (2 edn) [as 1873].
1883		Punch 3 Nov. 210/1: But what’s that to us, so’s we pull in the mopusses.
1896		M. Williams Round London 23: They haven’t got any mopusses, Jim; that’s what’s the matter. They’re all stone broke.
1900		Bulletin (Sydney) 24 Nov. 15/2: The bushie swaggered down the street to see what he could see, / And fell in with a pretty girl, who said ‘Now come with me’ / [...] / Then fled away his mopusses, with a whiz, whiz, whiz.
1905		Bluefield Daily Tel. (WV) 11 Mar. 4/2: In addition [...] the following [names for money] are given: [...] Moppus.
1936		Nottingham Eve. Post 9 Oct. 5/4: Some synonyms for money are simply fanciful [...] Why ’darby,’ or ‘mopusses’ or ‘stumpy,’ or a hundred others?