Green’s Dictionary of Slang

(UK Und.) a shirt, a smock; a sheet.

1665		Head Eng. Rogue I 48: Mish, A Shirt.
1674		Head Canting Academy (2nd edn).
1684		W. Nevison in Newgate Calendar I (1926) 291: ‘Now,’ saith he, ‘that thou art entered into our fraternity, thou must not scruple to act any villainies which thou shalt be able to perform, whether it be to nip a bung, bite the Peter Cloy, [...] or to cloy a mish from the crack man’s.’.
c.1698		B.E. Dict. Canting Crew n.p.: Mish c. a Shirt or Smock.
1703		Hell Upon Earth 5: Mish, a Shirt.
1707		‘Maunder’s Praise of His Strowling Mort’ in Farmer Musa Pedestris (1896) 33: What though I no togeman wear, / Nor commission, mish, or slate; / Store of strammel we’ll have here, / And ith’ skipper lib in state.
1718		C. Hitchin Regulator 19: Mishes, alias Shirts.
1728		Defoe Street Robberies Considered 33: Mish, a Smock.
1734		C. Johnson Hist. of Highwaymen &c. 105: [as cit. 1684].
1737, 1759, 1760, 1776		Bailey Universal Etym. Eng. Dict. n.p.: mish Shirt, Smock, or Shee.
1754		Scoundrel’s Dict. 19: A Shirt – Mish.
1768		(con. 1710–25) Tyburn Chronicle II in Groom (1999) xxix: A Mish A Shirt.
1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue.
1811		Lex. Balatronicum.
1823		Egan Grose’s Classical Dict. of the Vulgar Tongue.
1833		‘A Shove In The Mouth’ in Regular Thing, And No Mistake 61: And remember the mish that I brought you before / You went up to stare the big wig.
1859, 1860		Hotten Dict. of Modern Sl. etc.
1864, 1867, 1870		Hotten Sl. Dict.
1914		E. Wittmann ‘Clipped Words’ in DN IV:ii 132: mish, from commission. A shirt or chemise.
2019		P. Baker Fabulosa 290/1: camisa, commision, mish a shirt.