Art-studio subject
I believe the answer is:
<span class="explanation-format__ClueExplanation">I believe this clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">art</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(nude is a kind of art)</span><br/ ><br/ >'<span class="explanation-format__original">studio subject</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ ></span>
(Other definitions for nude that I've seen before include "Flesh-coloured" , "Having nothing on" , "Completely unclothed" , "totally exposed" , "Naked art subject" .)