quiescency vs inactivity

quiescency and inactivity both are nouns.

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

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

Other hypernyms of quiescency include inaction, inactiveness.

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