An invalid argument or conclusion is wrong because it is based on a mistake. We think that those arguments are rendered invalid by the hard facts on the ground. someone who cannot look after themselves because of illness, old age, or injury
In the Multi-Curve Option, this word appears when there is no curve stored in a selected memory location
If an action, procedure, or document is invalid, it cannot be accepted, because it breaks the law or some official rule. The trial was stopped and the results declared invalid
Having no force, effect, or efficacy; void; null; as, an invalid contract or agreement
someone who is incapacitated by a chronic illness or injury force to retire, remove from active duty, as of firemen no longer valid; "the license is invalid"