Woman's light dressing gown (8)
I believe the answer is:
negligee
'woman's light dressing gown' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for negligee that I've seen before include "Diaphanous dressing-gown" , "Woman's flimsy nightgown" , "Woman's light and flimsy dressing gown" , "Lady's diaphanous dressing gown" , "Nightie" .)