shininess vs radiance

shininess and radiance both are nouns.

Word	Noun	Adjective	Verb	Adverb
shininess	Yes	No	No	No
radiance	Yes	No	No	No

As nouns, radiance is a hypernym of shininess; that is, radiance is a word with a broader meaning than shininess:

shininess: the visual property of something that shines with reflected light
radiance: the quality of being bright and sending out rays of light

Other hypernyms of shininess include effulgence, radiancy, refulgence, refulgency, shine.

shininess (noun)	radiance (noun)
the visual property of something that shines with reflected light	the quality of being bright and sending out rays of light
	the amount of electromagnetic radiation leaving or arriving at a point on a surface
	an attractive combination of good health and happiness