Cop in male form (9)
I believe the answer is:
policeman
'cop in male form' is the definition.
'policeman' can be an answer for 'cop' (I've seen this in another clue). I am unsure of the 'in male form' bit.
'cop in male form' is the wordplay.
'form' is an anagram indicator (another form of the letters).
'cop'+'in'+'male'='copinmale'
'copinmale' anagrammed gives 'POLICEMAN'.
Can you help me to learn more?
(Other definitions for policeman that I've seen before include "Member of the force" , "Bobby" , "He's responsible for the maintenance of public order" , "Law enforcer" , "Open claim (anag.)" .)