vt to make or render invalid or infirm.
2. invalid ·vt to classify or enroll as an invalid.
3. invalid ·adj of no force, weight, or cogency; not valid; weak.
4. invalid ·noun not well; feeble; infirm; sickly; as, he had an invalid daughter.
5. invalid ·adj having no force, effect, or efficacy; void; null; as, an invalid contract or agreement.
6. invalid ·adj a person who is weak and infirm; one who is disabled for active service; especially, one in chronic ill health.