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knuckle-duster

American  
[nuhk-uhl-duhs-ter] / ˈnʌk əlˌdʌs tər /

noun

  1. brass knuckles.

knuckle-duster British  

noun

  1. (often plural) a metal bar fitted over the knuckles, often with holes for the fingers, for inflicting injury by a blow with the fist

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of knuckle-duster

An Americanism dating back to 1855–60

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.