Down Under soldier (5)
I believe the answer is:
anzac
'down under soldier' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for anzac that I've seen before include "World War One Australian or NZ soldier" , "digger" , "Commonwealth soldier" , "World War One Antipodean soldier" , "Planet rotates about it" .)