Judo grade (3)
I believe the answer is:
dan
'judo grade' is the definition.
(ranking system in Judo)
This is all the clue.
(Other definitions for dan that I've seen before include "Black-belt grade of proficiency" , "-- Dare, comic hero" , "Tribe" , "Level of competence in judo" , "Man's name; judo grade" .)