Classic art subject (4)
I believe the answer is:
nude
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">classic art subject</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for nude that I've seen before include "Completely unclothed" , "totally exposed" , "Naked figure" , "Wearing no clothes" , "Wearing one's birthday suit" .)