Bedtime garment (7)
I believe the answer is:
nightie
'bedtime garment' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for nightie that I've seen before include "Familiar bed-wear for woman" , "Loose garment" , "Sleeping attire" , "Female article of clothing" , "Sleeping garment" .)