Legal official (6)
I believe the answer is:
notary
'legal official' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for notary that I've seen before include "One authorised to certify legal documents" , "legal worker" , "Official working on legal documents" , "One authorised to perform certain legal functions" , "Solicitor authorised to administer oaths and certify documents" .)