Wise old man (6)
I believe the answer is:
nestor
'wise old man' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for nestor that I've seen before include "wise old king of Pylos" , "Greek hero and wise counsellor" , "Sage" , "Oldest, wisest Greek (Trojan Wars)" , "Wise counsellor of ancient Greece" .)