Men wanting a not-half clever person to give advice (6)
I believe the answer is:
oracle
'person to give advice' is the definition.
'men wanting a not-half clever' is the wordplay.
'men' becomes 'or' (I've seen this in other clues).
'wanting' means one lot of letters go next to another.
'not half' indicates taking half.
'clever' cut in half is 'cle'.
'or'+'a'+'cle'='ORACLE'
(Other definitions for oracle that I've seen before include "Place where ancient Greeks consulted gods, as at Delphi" , "Bringer of divine revelation" , "Where advice or prophecy was sought from the gods in ancient Greece" , "Source of information" , "Source of prophecies" .)