During spree kept producing smell (4)
I believe the answer is:
reek
'smell' is the definition.
(reek is a kind of smell)
'during spree kept producing' is the wordplay.
'during' indicates the answer is hidden within the clue.
'REEK' can be found hidden inside 'spree kept producing'.
(Other definitions for reek that I've seen before include "Smell strongly" , "Pong" , "bad odour" , "Smell unpleasant" , "Smell, like a Kerry mountain?" .)