Top Olympian (4)
I believe the answer is:
zeus
'top olympian' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for zeus that I've seen before include "God whose statue was one of the Seven Wonders" , "Celestial ruler" , "Chief Olympian deity" , "Supreme god of ancient Greek mythology" , "Chief Greek god" .)