invalid vs expired

invalid is a noun but expired is not a noun.

Word	Noun	Adjective	Verb	Adverb
invalid	Yes	Yes	Yes	No
expired	No	Yes	No	No

invalid (noun)	expired (noun)
someone who is incapacitated by a chronic illness or injury

invalid (adjective)	expired (adjective)
having no cogency or legal force	having come to an end or become void after passage of a period of time
no longer valid

invalid (verb)	expired (verb)
injure permanently
force to retire, remove from active duty, as of firemen