Max —, artist (5)
I believe the answer is:
ernst
I believe this clue is a double definition.
'max' is the first definition.
(I've seen this before)
'artist' is the second definition.
(max ernst)
(Other definitions for ernst that I've seen before include "Max __; Dadaist" , "artist's name" , "Max --, German painter" , "German-born painter, Max, co-founder of dadaism, d. 1976" , "Surrealist; stern (anag.)" .)