passivity vs inactiveness

passivity and inactiveness both are nouns.

Word	Noun	Adjective	Verb	Adverb
passivity	Yes	No	No	No
inactiveness	Yes	No	No	No

As nouns, inactiveness is a hypernym of passivity; that is, inactiveness is a word with a broader meaning than passivity:

Other hypernyms of passivity include inactivity, inertia.

passivity (noun)	inactiveness (noun)
the trait of remaining inactive; a lack of initiative	a disposition to remain inactive or inert
submission to others or to outside influences	the state of being inactive