Loose-fitting undergarment (7)
I believe the answer is:
chemise
'loose-fitting undergarment' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for chemise that I've seen before include "Woman's sleeveless undergarment" , "garment" , "Loose-fitting dress without a waist" , "Loose-fitting shirtlike dress" , "Loose dress" .)