Fire resulting from shared cig... (9)
I believe the answer is:
discharge
'fire' is the definition.
(I know that fire can be written as discharge)
'resulting from shared cig' is the wordplay.
'resulting from' indicates anagramming the letters.
'shared'+'cig'='sharedcig'
'sharedcig' anagrammed gives 'DISCHARGE'.
(Other definitions for discharge that I've seen before include "Fire (a gun); release from custody" , "empty" , "meet" , "Acquit" , "Dismiss (from a job)" .)