An Italian paste made of flour and eggs. Also a fop: which name arose from a club, called the Maccaroni Club, instituted by some of the most dressy travelled gentlemen about town, who led the fashions; whence a man foppishly dressed, was supposed a member of that club, and by contraction styled a Maccaroni.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
lye * mace coveNathan Bailey's 1721 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes