One that draws a long bow, a dealer in the marvellous, a teller of improbable stories, a liar: perhaps from the wonderful shots frequently boasted of by archers.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
Bow-wow Shop * To Box the CompassNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes