Loose dress or blouse (5)
I believe the answer is:
smock
'loose dress or blouse' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for smock that I've seen before include "Loose dress or blouse" , "Loose outer garment" , "Artist's loose overall" , "Loose overall or dress" , "Artist's, peasant's, overall" .)