Part of a nun's habit (6)
I believe the answer is:
wimple
'part of a nun's habit' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for wimple that I've seen before include "Woman's veil of old" , "Woman's old headdress, worn by some nuns now" , "Old headdress for a nun" , "Amazon country" , "A bit of a habit?" .)