knuckle duster vs knucks

knuckle duster and knucks both are nouns.

Word	Noun	Adjective	Verb	Adverb
knuckle duster	Yes	No	No	No
knucks	Yes	No	No	No

As nouns, knuckle duster and knucks are synonyms defined as:

knuckle duster and knucks: (used in the plural) a small metal weapon; worn over the knuckles on the back of the hand

Other synonyms of knuckle duster include brass knuckles, brass knucks, knuckles.

knuckle duster (noun)	knucks (noun)
(used in the plural) a small metal weapon; worn over the knuckles on the back of the hand	(used in the plural) a small metal weapon; worn over the knuckles on the back of the hand