Pillage can cause pain when there are soldiers about (6)
I believe the answer is:
rapine
'pillage' is the definition.
(I know that rapine is a type of pillage)
'cause pain when there are soldiers about' is the wordplay.
I cannot really understand how this works, but
'cause' could be 'pi' (PI is an example) and 'pi' is present in the answer.
'when' could be 'e' (I've seen this in other clues) and 'e' is found within the answer.
'are' could be 'ran' (running is a kind of being) and 'ran' is found in the leftover letters.
This accounts for all the letters.
This explanation may well be incorrect...
'can' acts as a link.
Can you help me to learn more?
(Other definitions for rapine that I've seen before include "Violent seizure of property" , "Spoiling" .)