knuckleduster

n (US brass knuckles) metal cover worn over the knuckles to increase the injury caused by a blow with the fist 戴在指关节上的金属套（打人时加重损伤）.

knot, knot-hole, knotty, know, know about, know better than, know no bounds, know of, know sb. by name, know-all, know-how, knowing, knowingly, knowledgable, knowledge, knowledgeable, knowledgeably, known, known as, knuckle, knucklehead, KO, koala, kobo, kohl, kohlrabi, kola, kook, kookaburra, kooky, kopeck (also kopek), koppie (also kopje), Koran, Koranic, Korea, Korean, kosher, koumiss, kowtow, kph,