Clerk never hides books (6)
I believe the answer is:
notary
'clerk' is the definition.
(thesaurus)
'never hides books' is the wordplay.
'never' becomes 'nary' (I've seen this in other clues).
'hides' is an insertion indicator.
'books' becomes 'ot' (Old Testament).
'nary' enclosing 'ot' is 'NOTARY'.
(Other definitions for notary that I've seen before include "Person who may certify legal documents" , "Public records official" , "Person legally authorised to witness signatures" , "Legal clerk" , "Official legally authorised to witness signatures" .)