Rules of behaviour for officer to keep to (8)
I believe the answer is:
protocol
'rules of behaviour' is the definition.
(I've seen this before)
'for officer to keep to' is the wordplay.
'for' becomes 'pro' (as in being 'pro' something).
'officer' becomes 'col' (short for colonel).
'to keep' means one lot of letters goes inside another.
'pro'+'col'='procol'
'procol' going around 'to' is 'PROTOCOL'.
(Other definitions for protocol that I've seen before include "Official code of conduct for a group" , "Approved procedure" , "Procedure or system of rules" , "Diplomatic rules" , "Formal code" .)