Stiff silky fabric (7)
(Other definitions for taffeta that I've seen before include "Shiny silk with a crisp texture" , "Sheeny fabric" , "Fine crisp lustrous fabric" , "Fabric - fat fate (anag)" , "Lustrous silky fabric" .)
(Other definitions for organza that I've seen before include "Silk (or silk-like) fabric" , "Transparent silky material" , "Silky cloth" , "Transparent silk material" , "Thin stiff natural or synthetic fabric" .)