INVAL'ID, adjective [Latin invalidus; in and validus, strong, from valeo, to be strong, to avail.]
1. Weak, of no force, weight or cogency.
2. In law, having no force, effect or efficacy; void; null; as an invalid contract or agreement.
IN'VALID, noun [Latin invalidus, supra.]
1. A person who is weak and infirm; a person sickly or indisposed.
2. A person who is infirm, wounded, maimed, or otherwise disabled for active service; a soldier or seaman worn out in service. The hospitals for invalids at Chelsea and Greenwich, in England, are institutions honorable to the English nation.