possession vs firmness

possession and firmness both are nouns.

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

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

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

possession (noun)	firmness (noun)
anything owned or possessed	the quality of being steady or securely and immovably fixed in place
the act of having and controlling property	the trait of being resolute
(sport) the act of controlling the ball (or puck)	the property of being unyielding to the touch
the trait of resolutely controlling your own behavior	the muscle tone of healthy tissue
a territory that is controlled by a ruling state
a mania restricted to one thing or idea
being controlled by passion or the supernatural