Elegant dress (4)
I believe the answer is:
gown
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">elegant dress</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for gown that I've seen before include "Garment (academic, formal, or protective)" , "A woman's long dress, or an informal dressing garment" , "Academic robe" , "Dress for formal occasions" , "Ball dress" .)