This officer is not particular (7)
I believe the answer is:
general
I believe this clue is a double definition.
'this officer' is the first definition.
(general is a kind of officer)
'not particular' is the second definition.
(I've seen this in another clue)
'is' acts as a link.
(Other definitions for general that I've seen before include "High-ranking officer" , "Not specialised or limited" , "top brass" , "Senior military officer" , "position" .)