Valid

What is Valid ?

Valid is (adj) 1. which is acceptable because it is true That is not a valid argument or excuse. She made several valid points in her speech. 2. which can be lawfully used for a time Travellers must have a valid ticket before boarding the train. I have a season ticket which is valid for one year. He was carrying a valid passport.

 

source: Easier English, Student Dictionary Upper Intermediate Level