Like a smokestack (5)
I believe the answer is:
sooty
'like a smokestack' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for sooty that I've seen before include "4 [BEAR]" , "black marks" , "TV glove puppet" , "Hand-puppet TV bear" , "Covered in black dust" .)