inactive vs activity

inactive is not a noun while activity is a noun.

Word	Noun	Adjective	Verb	Adverb
inactive	No	Yes	No	No
activity	Yes	No	No	No

inactive (noun)	activity (noun)
	any specific behavior
	the trait of being active; moving or acting rapidly and energetically
	an organic process that takes place in the body
	a process existing in or produced by nature (rather than by the intent of human beings)
	the state of being active
	(chemistry) the capacity of a substance to take part in a chemical reaction

inactive (adjective)	activity (adjective)
(military) not involved in military operations
not active physically or mentally
(pathology) not progressing or increasing; or progressing slowly
lacking activity; lying idle or unused
lacking in energy or will
(of e.g. volcanoes) not erupting and not extinct
not exerting influence or change
not engaged in full-time work
not in physical motion
(chemistry) not participating in a chemical reaction; chemically inert