Entry 2 senses · 2 variants Webster, 1913 cosh · IPA /kɒʃ/ n. v. t. 01 n. a piece of leather-covered metal with a flexible handle; used for hitting people. 1. a piece of leather-covered metal with a flexible handle; used for hitting people.[slang] Syn. blackjack, sap. 02 v. t. to hit (someone) with a cosh or similar bludgeon, usually on the head. 1. to hit (someone) with a cosh or similar bludgeon, usually on the head.[slang]