Soldiers give up and fall back (6)
I believe the answer is:
recede
'fall back' is the definition.
('recede' can be a synonym of 'fall back')
'soldiers give up' is the wordplay.
'soldiers' becomes 're' (Royal Engineers).
'give up' becomes 'cede' ('cede' can be a synonym of 'give up'**).
're'+'cede'='RECEDE'
'and' is the link.
(Other definitions for recede that I've seen before include "Withdraw" , "Go backwards" , "Start balding" , "Decree (anag) - ebb" , "Go back, ebb" .)