Lustrous, silky fabric (7)
I believe the answer is:
taffeta
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">lustrous silky fabric</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 taffeta that I've seen before include "Stiff shiny material" , "silky stuff" , "Thin glossy silk fabric" , "Fabric -- a fat eft (anag)" , "Shiny silk fabric" .)