Elite soldiers police volunteers without aggression (7,6)
I believe the answer is:
special forces
'elite soldiers police' is the definition.
I know nothing about this answer so I can't judge whether it can be defined by this definition.
'volunteers without aggression' is the wordplay.
'volunteers' becomes 'specials' (I can't justify this - if you can you should believe this answer much more).
'without' is an insertion indicator ('without' can be similar in meaning to 'outside').
'aggression' becomes 'force' (force is a kind of aggression).
'specials' placed around 'force' is 'SPECIAL FORCES'.
Can you help me to learn more?
(Another definition for special forces that I've seen is " Eg, SAS, SBS".)