valid Definition
valid adjective
1. unexpired: usable or acceptable until a fixed expiration date or under specific conditions of use
a valid passport
2. justifiable: reasonable or justifiable in the circumstances
That’s a valid question.
3. effective: bringing about the results or ends intended
regards the test as a valid measure of student performance
4. law legally binding: having binding force in law
5. logic logical: having premises from which the conclusion follows logically
It’s a perfectly valid argument.
[Late 16th century. Directly or via French