Transparent fabric (7)
'transparent fabric' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for chiffon that I've seen before include "dress material" , "Light silk/nylon fabric" , "Sheer silk or rayon fabric" , "Fine transparent fabric" , "Thin light fabric" .)
(Other definitions for organza that I've seen before include "Silk (or silk-like) fabric" , "Thin material" , "Silky cloth" , "Transparent silky material" , "Thin stiff natural or synthetic fabric" .)