rabidity vs rabidness

rabidity and rabidness both are nouns.

Word	Noun	Adjective	Verb	Adverb
rabidity	Yes	No	No	No
rabidness	Yes	No	No	No

As nouns, rabidity and rabidness are synonyms defined as:

Other synonyms of rabidity include madness.

rabidity (noun)	rabidness (noun)
unrestrained excitement or enthusiasm	unrestrained excitement or enthusiasm
The property of being very extreme, unreasonable, or fanatical in opinion; excessively zealous; comparable to one with rabies.