ZAD,
crooked, like the letter Z; as, A meer Zad, used of any bandy-legg'd, crouch-back'd or deformed Person.
crooked, like the letter Z; as, A meer Zad, used of any bandy-legg'd, crouch-back'd or deformed Person.
Entry taken from 1736 Canting Dictionary, by Nathan Bailey.
Zad in the 1811 Vulgar Tongue
Also see examples in Canting Songs and Slang Rhymes collected by John S. Farmer (1896).