Smooth fabric (5)
I believe the answer is:
satin
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">smooth fabric</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 satin that I've seen before include "Rich cloth" , "Lustrous fabric" , "Smooth and silky" , "Stain on shiny fabric" , "Stain on shiny cloth" .)