radiancy vs gleaming

radiancy and gleaming both are nouns.

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

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

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

radiancy (noun)	gleaming (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 (adjective)	gleaming (adjective)
	bright with a steady but subdued shining