The detachment's not in position (7)
I believe the answer is:
outpost
'the detachment's' is the definition.
The answer and definition can be both groups as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'not in position' is the wordplay.
'not in' becomes 'out' ('out' is the opposite to 'in').
'position' becomes 'post' (synonyms).
'out'+'post'='OUTPOST'
Can you help me to learn more?
(Other definitions for outpost that I've seen before include "Small group of soldiers" , "Small camp some distance away from the main army" , "Distant office, settlement" , "Remote military site" , "Remote military camp" .)