He may produce stupor - in his readers? (6)
I believe the answer is:
proust
'his readers?' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'he may produce stupor' is the wordplay.
'stupor' can be anagrammed to 'PROUST'.
Though, I'm not sure how the anagram is indicated.
'in' is the link.
Can you help me to learn more?
(Other definitions for proust that I've seen before include "Famous French novelist in stupor" , "French author" , "Great French writer in stupor" , "Marcel --, French novelist 1871-1922" , "French novelist - stupor (anag)" .)