Celebrated Surrealist (5)
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">celebrated surrealist</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for ernst that I've seen before include "Max -, twentieth century German Surrealist artist" , "artist's name" , "Young partner" , "German-born painter, Max, co-founder of dadaism, d. 1976" , "Surrealist; stern (anag.)" .)