quiescency vs inactiveness

quiescency and inactiveness both are nouns.

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

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

Other hypernyms of quiescency include inaction, inactivity.

quiescency (noun)	inactiveness (noun)
quiet and inactive restfulness	a disposition to remain inactive or inert
a state of quiet (but possibly temporary) inaction	the state of being inactive