Other forms: valider
A valid argument is one that is well-grounded in fact, law or logic. "Their argument for annulment was valid because they had never even met and their marriage was the result of a clerical error at town hall."
Something is valid when it can be supported or backed-up, or if it is functional: “She figured her password was valid because she had just set it.” In a legal context, valid means that something is binding or actionable: “At the time of the accident his license was no longer valid, so they impounded his car.” The logical grounding of an argument can be valid: “That’s a valid point about Santa being too large to fit down a chimney.”