What is "cold cock"

alt. (context slang English) A small heavy object used to give additional force to a punch or other blow of the hand. n. (context slang English) A small heavy object used to give additional force to a punch or other blow of the hand. vb. 1 (context slang English) To hit someone with a cold cock. 2 (context slang English) To hit someone with a club, bottle, or any object that gives additional force to the blow. 3 (context slang English) To knock someone unconscious.