Lustrous cotton fabric (6)
I believe the answer is:
sateen
'lustrous cotton fabric' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for sateen that I've seen before include "Glossy material" , "Cotton fabric with a satiny finish" , "Closely woven cotton fabric resembling satin" , "Shiny cloth found in senate" , "Cotton fabric with a shiny finish" .)