Part of boxing once mismanaged (4)
I believe the answer is:
cone
'part' is the definition.
(I know that cone has the is a more specific form of the action bevel)
'boxing once mismanaged' is the wordplay.
'once' can be anagrammed to 'CONE'.
However, I'm not sure how this is indicated.
'of' is the link.
Can you help me to learn more?
(Other definitions for cone that I've seen before include "standing in middle of motorway" , "Tapering object" , "Motorway menace" , "Movable plastic bollard" , "Ice cream holder" .)