Derivative from "Dicklock" as made popular by Bubbles of the hit TV show "Trailer Park Boys".

A dick lock being someone who cant get laid. A numb lock is a nerd who cannot get laid and plays with the numlock key while Masturbating.
Q: Hey where's Simon ?

A: Oh that "Numlock" hes at home fapping off.
by DunkyHazard February 4, 2010
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