Green’s Dictionary of Slang

smish n.

a shirt.

1741		Canting Academy, or the Pedlar’s-French Dict. 112: A Shirt A Smish.
1753		J. Poulter Discoveries (1774) 43: Calp, Noll, and Smish; Hat, Wig, and Shirt.
1786		Whole Art of Thieving [as cit. 1753].
1790		‘The Bowman Prigg’s Farewell’ in Wardroper (1995) 283: My smish and my joseph I leave / And the rest of my duds all behind me.
1807		H. Tufts Autobiog. (1930) 292: Smish signifies a shirt.
1812		Vaux Vocab. of the Flash Lang.
1859, 1860		Hotten Dict. of Modern Sl. etc.
1861		(con. 1840s–50s) H. Mayhew London Labour and London Poor I 217/2: I give below a vocabulary of their talk to each other: [...] Smeesh .... A shift.
1864, 1867, 1870		Hotten Sl. Dict.
1873		Sl. Dict.
1887		Daily Trib. (Bismarck, ND) 23 Oct. 4/1: A shirt is a ‘smish;’ shoes are ‘skates.’.
1895		Crowe Aus. Sl. Dict. 76: Smish, a shirt or chemise.