·vt To make or render invalid or infirm.
II. Invalid ·vt To classify or enroll as an invalid.
III. Invalid ·adj Of no force, weight, or cogency; not valid; weak.
IV. Invalid ·noun Not well; feeble; infirm; sickly; as, he had an invalid daughter.
V. Invalid ·adj Having no force, effect, or efficacy; void; null; as, an invalid contract or agreement.
VI. Invalid ·adj A person who is weak and infirm; one who is disabled for active service; especially, one in chronic ill health.