Sort of headgear to use when one is smoking? (9)
I believe the answer is:
stovepipe
This clue is a double definition.
'sort of headgear' is the first definition.
'to use when one is smoking?' is the second definition.
(Other definitions for stovepipe that I've seen before include "Cooker-to-roof duct" , "Metal chimney up to a flue" , "Flue; type of hat" , "Tall hat" , "Flue from oven" .)