One very brave Roman leader? Not quite (4)
I believe the answer is:
hero
'one very brave' is the definition.
(a very brave person)
'roman leader? not quite' is the wordplay.
'roman leader?' becomes 'herod' (Herod, king of Judea in the Roman Empire).
'not quite' means to remove the last letter.
'herod' with its final letter taken off is 'HERO'.
(Other definitions for hero that I've seen before include "Man of great courage and deeds" , "Lion" , "victor" , "Priestess at Sestos" , "Conqueror" .)