District with soldiers undermining religious group (6)
I believe the answer is:
sector
'district' is the definition.
(thesaurus)
'soldiers undermining religious group' is the wordplay.
'soldiers' becomes 'or' (Other Rank).
'undermining' means one lot of letters go next to another.
'religious group' becomes 'sect' (I've seen this before**).
'or' after 'sect' is 'SECTOR'.
'with' acts as a link.
(Other definitions for sector that I've seen before include "Specific group as part of the economy" , "Distinct part (of, eg, economy)" , "Division of a nation's economy" , "Area of circle between two radii" , "battle zone" .)