Belgian surrealist
I believe the answer is:
'belgian surrealist' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for magritte that I've seen before include "Belgian surreal painter" , "Belgian surrealist artist" , "RenZ -, Belgian artist" , "Belgian surrealist painter, d.1967" , "Rene -, Surrealist painter" .)