Olympian shows courage having lost lead (4)
I believe the answer is:
ares
'olympian' is the definition.
(Greek god who lived on Mount Olympus)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for ares that I've seen before include "Greek god of war" , "Land measures" , "Belligerent god" , "War-god" , "Olympian" .)