Disgraced boxing competition (4)
I believe the answer is:
race
'competition' is the definition.
(race is a kind of competition)
'disgraced boxing' is the wordplay.
'boxing' indicates a hidden word (the solution is contained or boxed up by the clue).
'RACE' can be found hidden inside 'disgraced'.
(Other definitions for race that I've seen before include "Career - people" , "See 23" , "Rapid current" , "People; run" , "eg The Oaks" .)