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Synonyms for Invalid (same or very similar meaning)

WordNet sense 1 (someone who is incapacitated by a chronic illness or injury):
shut-in

WordNet sense 2 (lacking any legal or binding force):
null, void

WordNet sense 3 (erroneous and usually accidental):
false

WordNet sense 4 (containing or based on a fallacy):
fallacious, unsound

WordNet sense 5 (not capable of being collected):
bad

WordNet sense 6 (injure permanently):
disable, handicap, incapacitate


From the ODE community, based on WordNetadd/edit