Green’s Dictionary of Slang

nig v.¹

to clip money.

1785

Grose Classical Dict. of the Vulgar Tongue.

In derivatives

nigging (n.)

clipping coins.

c.1698		B.E. Dict. Canting Crew n.p.: Nigging c. Clipping.
1725		New Canting Dict. [as cit. c.1698].
1737, 1759, 1760, 1776		Bailey Universal Etym. Eng. Dict. [as cit. c.1698].
1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue.
1811		Lex. Balatronicum.
1823		Egan Grose’s Classical Dict. of the Vulgar Tongue.