His work is his play (9)
I believe the answer is:
dramatist
'his play' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'his work is' is the wordplay.
I cannot quite see how this works, but
'work' could be 'drama' (I have seen 'Theatrical work ' mean 'drama' so perhaps 'work' could also mean 'drama') and 'drama' is present in the answer.
'is' is present in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for dramatist that I've seen before include "Shakespeare, say" , "O'Neill or O'Casey, for example" , "Coward, for example" , "One who writes plays" , "Pinter, say" .)