One girl's name for army manoeuvres (4)
I believe the answer is:
mary
'one girl's name' is the definition.
'army manoeuvres' is the wordplay.
'manoeuvres' indicates anagramming the letters.
'army' anagrammed gives 'MARY'.
'for' is the link.
(Other definitions for mary that I've seen before include "Sinner who became a follower of Jesus" , "Successor to Edward VI" , "feature of 21/23 [NATIVITY SCENE]" , "Mother of Jesus" , "O'Rourke, Harney and McAleese" .)