activity vs inactive

activity is a noun but inactive is not a noun.

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

activity (noun)	inactive (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

activity (adjective)	inactive (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