The judo expert? (3)
I believe the answer is:
dan
'the judo expert?' is the definition.
(ranking system in Judo)
This is the entire clue.
(Other definitions for dan that I've seen before include "Judo, karate level" , "Expertise level in juso" , "Grade of proficiency in judo" , "Judo level and Wicklow lake" , "Karate expert" .)