A weapon consisting of a metal reinforcement for the clenched fist, with finger holes molded in
Jacob always carried a set of brass knuckles, just in case he ever got caught up in a bar fight.
A metal chain or a set of rings attached to a bar that can be fitted over the fingers to increase the impact of a blow with the fist. a set of connected metal rings worn over a person's fingers, used as a weapon British Equivalent: knuckleduster