Soldiers handle move back (7)
I believe the answer is:
retreat
'move back' is the definition.
(synonyms)
'soldiers handle' is the wordplay.
'soldiers' becomes 're' (Royal Engineers).
'handle' becomes 'treat' (synonyms).
're'+'treat'='RETREAT'
(Other definitions for retreat that I've seen before include "It may be secluded" , "snug" , "Withdraw from battle" , "asylum" , "place for meditation" .)