obstinacy vs firmness

obstinacy and firmness both are nouns.

Word	Noun	Adjective	Verb	Adverb
obstinacy	Yes	No	No	No
firmness	Yes	No	No	No

As nouns, firmness is a hypernym of obstinacy; that is, firmness is a word with a broader meaning than obstinacy:

Other hypernyms of obstinacy include firmness of purpose, resoluteness, resolution, resolve.

obstinacy (noun)	firmness (noun)
the trait of being difficult to handle or overcome	the quality of being steady or securely and immovably fixed in place
resolute adherence to your own ideas or desires	the trait of being resolute
	the property of being unyielding to the touch
	the muscle tone of healthy tissue