definition of valid
Adj. 1. valid-well grounded in logic or truth or having legal force; a valid inference ; a valid argument ; a valid contract ; a valid license . Antonyms: invalid-having no cogency or legal force; invalid reasoning; an invalid driver's license.dj. 1. valid-well grounded in logic or truth or having legal force; a valid inference ; a valid argument ; a valid contract ; a valid license . Antonyms: invalid-having no cogency or legal force; invalid reasoning; an invalid driver's license.