As contracted, file a derogative opinion piece (6)
I believe the answer is:
leader
'as contracted file a derogative opinion piece' is the definition.
I can't tell whether this definition defines the answer.
'file a derogative opinion piece' is the wordplay.
'piece' indicates the answer is hidden within the clue.
'LEADER' is hidden within 'file a derogative opinion'.
Can you help me to learn more?
(Other definitions for leader that I've seen before include "Important (newspaper) article" , "Principal first violinist" , "Party head" , "Chief or front man" , "source of inspiration" .)