ardor vs fervor

ardor and fervor both are nouns.

Word	Noun	Adjective	Verb	Adverb
ardor	Yes	No	No	No
fervor	Yes	No	No	No

As nouns, ardor and fervor are synonyms defined as:

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

ardor (noun)	fervor (noun)
intense feeling of love	feelings of great warmth and intensity
a feeling of strong eagerness (usually in favor of a person or cause)	the state of being emotionally aroused and worked up
feelings of great warmth and intensity