fervidness vs fervour

fervidness and fervour both are nouns.

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

As nouns, fervidness and fervour are synonyms defined as:

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

fervidness (noun)	fervour (noun)
feelings of great warmth and intensity	feelings of great warmth and intensity
	the state of being emotionally aroused and worked up