Martial arts expert (5,4)
I believe the answer is:
black belt
'martial arts expert' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for black belt that I've seen before include "It's worn by a Karate expert" , "Recognition of prowess in martial arts" , "Rank in the martial arts" , "Combat ace" , "Proficient martial artist" .)