Invalid

(a.) Of no force, weight, or cogency; not valid; weak.

Invalid - Other Definitions

(a.) Of no force, weight, or cogency; not valid; weak.
(a.) Having no force, effect, or efficacy; void; null; as, an invalid contract or agreement.
(a.) A person who is weak and infirm; one who is disabled for active service; especially, one in chronic ill health.
(n.) Not well; feeble; infirm; sickly; as, he had an invalid daughter.
(v. t.) To make or render invalid or infirm.
(v. t.) To classify or enroll as an invalid.