inactivity vs stoppage

inactivity and stoppage both are nouns.

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

As nouns, stoppage is a hyponym of inactivity; that is, stoppage is a word with a more specific, narrower meaning than inactivity:

inactivity (noun)	stoppage (noun)
being inactive; being less active	the act of stopping something
a disposition to remain inactive or inert	an obstruction in a pipe or tube
the state of being inactive	the state of inactivity following an interruption