fervidness vs fervency

fervidness and fervency both are nouns.

Word	Noun	Adjective	Verb	Adverb
fervidness	Yes	No	No	No
fervency	Yes	No	No	No

As nouns, fervidness and fervency are synonyms defined as:

Other synonyms of fervidness include ardor, ardour, fervor, fervour, fire.

fervidness (noun)	fervency (noun)
feelings of great warmth and intensity	feelings of great warmth and intensity