What smoker craves? Contrary habit! (4)
I believe the answer is:
drag
'habit' is the definition.
The definition and answer can be both acts as well as being singular nouns.
Maybe you can see an association between them that I can't see?
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for drag that I've seen before include "Bind" , "Tedious experience" , "Pull along the ground - transvestite'-'s get-up" , "A bore (colloq.); lug" , "Pull against a resistance" .)