Wanting courage primarily to stop fright (6)
I believe the answer is:
scarce
'wanting' is the definition.
(I've seen this before)
'courage primarily to stop fright' is the wordplay.
'primarily' indicates taking the first letters.
'to stop' is an insertion indicator.
'fright' becomes 'scare' (scare is a kind of fright**).
The initial letter of 'courage' is 'c'.
'c' placed within 'scare' is 'SCARCE'.
(Other definitions for scarce that I've seen before include "Common? Definitely not" , "Scant, meagre" , "Insufficient to meet demand" , "Rare shock Conservative getting in" , "Rarely seen" .)