Fair on managing boxing event that's gruelling
I believe the answer is:
iron man
'event that's gruelling' is the definition.
I can't judge whether this defines the answer.
'fair on managing boxing' is the wordplay.
'boxing' indicates a hidden word (the solution is contained or boxed up by the clue).
'IRON-MAN' is hidden within 'fair on managing'.
Can you help me to learn more?
(Other definitions for iron man that I've seen before include "one of great strength" , "Endurance competition" , "endurance event" , "Tough event" , "fellow of great strength" .)