radiancy vs sheen

radiancy and sheen both are nouns.

Word	Noun	Adjective	Verb	Adverb
radiancy	Yes	No	No	No
sheen	Yes	No	No	No

As nouns, sheen is a hyponym of radiancy; that is, sheen is a word with a more specific, narrower meaning than radiancy:

Other hyponyms of radiancy include gleam, gleaming, glow, lambency, luster, lustre, shininess, burnish, gloss, glossiness, polish.

radiancy (noun)	sheen (noun)
the quality of being bright and sending out rays of light	the visual property of something that shines with reflected light