Erroneous or unrecognizable because of a flaw in reasoning or an error in input. Invalid results, for example, might occur if the logic in a program is faulty. Compare illegal.
1. Having no cogency or legal force
2. No longer valid
ETYM French invalide, Latin invalidus. Related to Invalid null.
Someone who is incapacitated by a chronic illness or injury; SYN. shut-in.
To force to retire, remove from active duty, as of firemen.