"invalid" in the noun sense
1. invalid, shut-in
someone who is incapacitated by a chronic illness or injury
"invalid" in the verb sense
1. invalid
force to retire, remove from active duty, as of firemen
2. disable, invalid, incapacitate, handicap
injure permanently
"He was disabled in a car accident"
"invalid" in the adjective sense
1. invalid
having no cogency or legal force
"invalid reasoning"
"an invalid driver's license"
2. invalid
no longer valid
"the license is invalid"
Source: WordNet® (An amazing lexical database of English)
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