The detachment is not in position (7)
I believe the answer is:
outpost
'the detachment' is the definition.
The definition and answer can be both groups as well as being singular nouns.
Perhaps there's a link between them 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'
'is' acts as a link.
Can you help me to learn more?
(Other definitions for outpost that I've seen before include "Distant military camp" , "Remote stronghold" , "Remote military site" , "Distant office, settlement" , "Distant station or branch" .)