23. Valid (adj) – that is legally or officially acceptable

e.g. The concept remains valid, but we must move forward with implementation.

24. witness (noun) – a person who gives evidence in a court of law

e.g. He is expected to be a key witness in the murder trial.

25. witness (verb)- (a document) to sign a document as a witness

e.g. Mr. Brown was invited to witness the will of his aunt.