Greek goddess of wisdom, daughter of Zeus (6)
I believe the answer is:
athena
I believe this clue is a double definition.
'greek goddess of wisdom' is the first definition.
(I've seen this before)
'daughter of zeus' is the second definition.
(I've seen this in another clue)
(Other definitions for athena that I've seen before include "wise but fierce goddess" , "Greek goddess of wisdom etc." , "One-time goddess" , "Greek goddess of a capital city" .)