Battle contributing to military prestige? (5)
I believe the answer is:
ypres
'battle' is the definition.
(I know that Ypres is a pitched battle)
'contributing to military prestige?' is the wordplay.
'contributing to' indicates a hidden word (the answer contributes to part of the clue ).
'YPRES' is hidden within 'military prestige'.
(Other definitions for ypres that I've seen before include "WW1 battle town" , "World War I battleground" , "scene of battle" , "WW1 battle site" , "Belgian World War One battle site" .)