Invalid

Part of speech: noun (n.)

A person who is weak and infirm; one who is disabled for active service; especially, one in chronic ill health.

Part of speech: verb (v.)

1. To make or render invalid or infirm. "Invalided, bent, and almost blind." Dickens.

2. To classify or enroll as an invalid. Peace coming, he was invalided on half pay. Carlyle.

Part of speech: adjective (a.)

1. Of no force, weight, or cogency; not valid; weak.

2. Having no force, effect, or efficacy; void; null; as, an invalid contract or agreement.

Part of speech: adjective (a.)

Not well; feeble; infirm; sickly; as, he had an invalid daughter.