Briefly judge (3)
I believe the answer is:
ref
'judge' is the definition.
(referee)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for ref that I've seen before include "A diminutive umpire in soccer or boxing" , "Football's whistler" , "One traditionally in black" , "In brief, he controls a soccer match" , "Middleman needing cards" .)