What can be used to conceal cigarette smell by doctor (5,4)
I believe the answer is:
smoke bomb
'doctor' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how one could define the other.
'what can be used to conceal cigarette smell' is the wordplay.
I cannot really understand how this works, but
'smell' could be 'bo' (informal abbreviation for body odour) and 'bo' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
'by' acts as a link.
Can you help me to learn more?
(Other definitions for smoke bomb that I've seen before include "Explosive causing little cloud" , "Pyrotechnic obscurant" , "this may cover aggressive activity" , "Weapon providing concealment" , "One set off to obscure" .)