A term of reproach to the puritans and partizans of Oliver Cromwell, and the Rump Parliament, who it is said made use of a bowl as a guide to trim their hair.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
Round Dealing * Round RobinNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes