Flemish painter (6)
I believe the answer is:
rubens
'flemish painter' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for rubens that I've seen before include "Peter Paul -, sixteenth-seventeenth century Flemish painter" , "Flemish painter, 1577-1640" , "Peter Paul --, artist" , "Flemish baroque artist" , "Sir Peter Paul ---, painter" .)