Longman Dictionary of Contemporary English
knuckle-duster
noun
EXAMPLES FROM CORPUS
▪ Before it was over, knuckle-dusters had been used and two of the combatants were taken to hospital.
▪ He employed it with the subtlety of a knuckle-duster.
▪ I then noticed one of them putting on to his fingers ... a knuckle-duster.
▪ There was still room on his desk for Dryden and Pope beside his knuckle-duster.
▪ They claimed to have the weapon purely for self-defence but also had a set of viciously spiked knuckle-dusters.
Wiktionary
knuckle-duster
n. (alternative spelling of knuckle duster English)
Usage examples of "knuckle-duster".
Using the heavy handguard like a knuckle-duster, she cracked him several times across the head.
As before, the Sanders wrappings were as uncluttered as gold bricks and the slanting autumn sunlight drew fire from the diamond knuckle-dusters.