Spanish cubist painter (7)
I believe the answer is:
picasso
'spanish cubist painter' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for picasso that I've seen before include "Pablo -, Spanish painter/sculptor" , "Prominent cubist" , "pioneer of Cubism" , "20th century painter" , "Pablo ,,,,,,,, great late Spanish artist" .)