shininess vs effulgence

shininess and effulgence both are nouns.

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

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

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

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

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