Principal bullfighter (7)
I believe the answer is:
matador
'principal bullfighter' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for matador that I've seen before include "who does for bulls" , "Spanish killer" , "Spaniard that fights" , "Performer in the Ring" , "Bullfighter who slays the bull" .)