Willie Wonka creator (4)
I believe the answer is:
'willie wonka creator' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for dahl that I've seen before include "Roald - - (deviser of Willy-Wonka)" , "Model" , "British writer of many children's books, d. 1990" , "Roald -, British writer" , "British author, notably of children's books, d.1990" .)