50 valid synonyms include well founded, sound, well grounded, reasonable, rational, logical, justifiable, defensible, defendable, and supportable. Valid is an adjective, and its antonyms are invalid, illegal, and void. Here are some additional synonyms for "valid" with example sentences.
50 other ways to say valid.
A valid passport is required here.
His argument is valid and logical.
She provided valid proof for verification.
The contract remains valid until expiration.
You require a valid ID to register.