Officer is more offensive (6)
I believe the answer is:
ranker
I believe this clue is a double definition.
'officer' is the first definition.
(ranker is a kind of officer)
'more offensive' is the second definition.
('rank' can be similar in meaning to 'offensive')
'is' is the link.
(Other definitions for ranker that I've seen before include "Private soldier" , "Tommy" , "Even more flagrant" , "one giving order" , "A private; an officer" .)