Showing extreme courage (6)
I believe the answer is:
heroic
'showing extreme courage' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for heroic that I've seen before include "Fearless, valiant" , "Showing extreme courage" , "Dramatic" , "Supremely courageous and brave" , "Surpassing the ordinary, in courage say" .)