The shopman of a bow-wow shop, or dealer in second hand clothes, particularly about Monmouth-Street, who walks before his master’s door, and deafens every passenger with his cries of—Clothes, coats, or gowns—what d’ye want, gemmen?—what d’ye buy? See Bow-wow Shop.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
See also the definition in Nathan Bailey's 1736 dictionary of canting and thieving slang.
Bargees * BarkshireNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes