Topless soldiers seen before end, shut in (7)
I believe the answer is:
enclose
'shut in' is the definition.
(synonyms)
'topless soldiers seen before end' is the wordplay.
'topless' means to remove the first letter.
'soldiers' becomes 'men' (men can mean a group of soldiers).
'seen before' means one lot of letters go next to another.
'end' becomes 'close' (close can mean the closing part of something).
'men' with its initial letter removed is 'en'.
'en'+'close'='ENCLOSE'
(Other definitions for enclose that I've seen before include "Hem in" , "Surround; place in envelope (with letter)" , "Bound" , "Cover" , "Put inside" .)