Valid

Rational

Synonyms: Well founded, well grounded, rational, justifiable, defendable, sustainable, workable, able to hold water, telling, bona fide, effective, convincing, believable, forceful, weighty, reliable, sound, reasonable, logical, defensible, supportable, maintainable, arguable, plausible, viable, cogent, powerful, credible, substantial, strong, authoritative, and vindicable.

Proper

Synonyms: Correct, legally acceptable, bona fide, official, lawful, licit, legally binding, contractual, in effect, authentic, proper, genuine, signed and sealed, legal, legitimate, binding, in force, and effective.

Example Sentences

His argument is valid and logical.

She provided valid proof for verification.

A valid passport is required here.

The contract remains valid until expiration.