To eat like a beggar man, and wag his under jaw; a jocular reproach to a proud man. To eat one’s words; to retract what one has said.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
Easy Virtue * To EdgeNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes