radiancy vs gleam

radiancy and gleam both are nouns.

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

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

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

radiancy (noun)	gleam (noun)
the quality of being bright and sending out rays of light	an appearance of reflected light
	a flash of light (especially reflected light)

radiancy (verb)	gleam (verb)
	to shine with faint or brief light
	shine brightly, like a star or a light
	be shiny, as if wet