Really excellent police officer (5)
I believe the answer is:
super
This might be a double definition.
'really excellent' is the first definition.
'super' can be an answer for 'excellent' (I've seen this before). I am unsure of the 'really' bit.
'police officer' is the second definition.
(term for a senior police officer)
Can you help me to learn more?
(Other definitions for super that I've seen before include "of high quality" , "Great; wonderful" , "Extremely good" , "Delightful" , "Marvellous, terrific" .)