Soldiers go and come back (6)
I believe the answer is:
return
'come back' is the definition.
(synonyms)
'soldiers go' is the wordplay.
'soldiers' becomes 'RE' (Royal Engineers).
'go' becomes 'turn' (turning is a kind of going).
're'+'turn'='RETURN'
'and' is the link.
(Other definitions for return that I've seen before include "Homecoming" , "second half of journey" , "Come back with a formal report on transactions" , "Come/go back" , "Interest" .)