Green’s Dictionary of Slang

nocky n.

[Suffolk dial.; ? f. the fool’s knocking on or knuckling of his forehead]

a fool, a simpleton.

[UK]B.E. Dict. Canting Crew n.p.: Nocky c. a silly, dull Fellow.
[UK]New Canting Dict. [as cit. c.1698].
[UK]Bailey Universal Etym. Eng. Dict. [as cit. c.1698].

In compounds