shut-in vs invalid

shut-in and invalid both are nouns.

Word	Noun	Adjective	Verb	Adverb
shut-in	Yes	Yes	No	No
invalid	Yes	Yes	Yes	No

As nouns, shut-in and invalid are synonyms defined as:

shut-in and invalid: someone who is incapacitated by a chronic illness or injury

shut-in (noun)	invalid (noun)
someone who is incapacitated by a chronic illness or injury	someone who is incapacitated by a chronic illness or injury

shut-in (adjective)	invalid (adjective)
confined usually by illness	having no cogency or legal force
somewhat introverted	no longer valid

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