Sad clown who makes wharf decay (7)
I believe the answer is:
pierrot
'sad clown who' is the definition.
Although both the answer and definition are singular nouns, I can't see how they can define each other.
'wharf decay' is the wordplay.
'wharf' becomes 'pier' (I've seen this before).
'decay' becomes 'rot' (rot can mean to decay).
'pier'+'rot'='PIERROT'
'makes' is the link.
Can you help me to learn more?
(Other definitions for pierrot that I've seen before include "Male clown from French pantomime" , "Clown from French pantomime with white face and costume - tripe or what?" , "French pantomime character with a white face" , "I report on French pantomime clown" , "Aged entertainer" .)