Frequenters of brothels. Also an impudent, brazen-faced fellow, perhaps from the Corinthian brass.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
Corinth * Cork-brainedNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes