Conductor's constipation appalling -- pot not needed (9)
I believe the answer is:
toscanini
'conductor's' is the definition.
(Arturo Toscanini)
'constipation appalling pot not needed' is the wordplay.
I cannot quite understand how this works, but
'pot' could be 'can' (synonyms) and 'can' is located in the answer.
'not' could be 'o' (I've seen this in other clues) and 'o' is present in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for toscanini that I've seen before include "Old conductor" , "Maestro" , "Acclaimed Italian conductor" , "Bare rock formation" , "Music director" .)