GIVE EVIDENCE FOR is a phrase that is used to ask for proof or validation of a claim. The crossword solutions VALIDATE (8 letters), AFFIDATE (8 letters), and ATTESTTO (8 letters) all refer to providing evidence to support a claim. VALIDATE means to confirm the truth or accuracy of something, affidate means to swear to the truth of something, and attestto means to bear witness to the truth of something. All three terms refer to providing evidence to back up a claim.