A hand. Tip us your mawley; shake hands. with me. Fam the mawley; shake hands.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
Mawkes * Maw-wallopNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes