Green’s Dictionary of Slang

a ragged vagrant, whose flesh can be seen through his garments.

c.1698		B.E. Dict. Canting Crew n.p.: Heathen Philosopher, a sorry poor tatter’d Fellow, whose Breech may be seen through his Pocket-holes.
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 n.p.: Heathen Philosopher. One whose breech may be seen through his pocket-hole: this saying arose from the old philosophers, many of whom depised the vanity of dress to such a point, as often to fall into the opposite extreme.
1811		Lex. Balatronicum.
1823		Egan Grose’s Classical Dict. of the Vulgar Tongue.