COLQUARRON,
a Man's Neck; as, His Colquarron is just about to be twisted. He is just going to be turn'd off.
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Entry taken from 1736 Canting Dictionary, by Nathan Bailey.
Colquarron in the 1811 Vulgar Tongue
Also see examples in Canting Songs and Slang Rhymes collected by John S. Farmer (1896).