Never lost courage (5)
I believe the answer is:
nerve
'courage' is the definition.
(nerve is a kind of courage)
'never lost' is the wordplay.
'lost' indicates an anagram.
'never' is an anagram of 'NERVE'.
(Other definitions for nerve that I've seen before include "Sensitive fibre in the body" , "Fibre to carry instructions between brain and body" , "Coolness under fire" , "Courage, coolness in danger" , "Bodily fibre that communicates sensations" .)