1. Adjective
Of no force, weight, or cogency; not valid; weak.
2. Adjective
Having no force, effect, or efficacy; void; null; as, an invalid contract or agreement.
3. Adjective
A person who is weak and infirm; one who is disabled for active service; especially, one in chronic ill health.
4. Noun
Not well; feeble; infirm; sickly; as, he had an invalid daughter.
5. Verb
To make or render invalid or infirm.
6. Verb
To classify or enroll as an invalid.
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