From Longman Dictionary of Contemporary Englishknuckle-dusterˈknuckle-ˌduster noun [countable] PMWa piece of metal that covers all the knuckles of the hand, used as a weapon
Examples from the Corpus
knuckle-duster• I then noticed one of them putting on to his fingers ... a knuckle-duster.• He employed it with the subtlety of a knuckle-duster.• There was still room on his desk for Dryden and Pope beside his knuckle-duster.• Before it was over, knuckle-dusters had been used and two of the combatants were taken to hospital.• They claimed to have the weapon purely for self-defence but also had a set of viciously spiked knuckle-dusters. 