Green’s Dictionary of Slang

a man wearing a notably large wig.

1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue.
1798		‘St Giles’s Greek’ in Sporting Mag. Dec. XIII 164/1: A poor old wiganowns flat was clerked at drop-a-cog by a couple of queer coves.
1811		Lex. Balatronicum.
1823		Egan Grose’s Classical Dict. of the Vulgar Tongue.