His was TWL, retiring to Parisian island (5)
I believe the answer is:
eliot
'his was twl' is the definition.
The definition suggests a singular noun which matches the answer.
'retiring to parisian island' is the wordplay.
'retiring' says the letters should be written in reverse.
'parisian island' becomes 'ile' (I can't explain this - if you can you should give a lot more credence to this answer).
'to'+'ile'='toile'
'toile' reversed gives 'ELIOT'.
Can you help me to learn more?
(Other definitions for eliot that I've seen before include "Pseudonymous writer" , "Murder in the Cathedral author" , "George - - (novelist)" , "Four Quartets poet" , "Practical Cats author" .)