radiancy vs effulgence

radiancy and effulgence both are nouns.

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

As nouns, radiancy and effulgence are synonyms defined as:

radiancy and effulgence: the quality of being bright and sending out rays of light

Other synonyms of radiancy include radiance, refulgence, refulgency, shine.

radiancy (noun)	effulgence (noun)
the quality of being bright and sending out rays of light	the quality of being bright and sending out rays of light