Off-smelling (6)
I believe the answer is:
rancid
I believe this is a double definition.
'off' is the first definition.
(I've seen this before)
'smelling' is the second definition.
(thesaurus)
(Other definitions for rancid that I've seen before include "(Of fatty foods) gone off" , "Fragmented bricks etc." , "(Of butter) gone off" , "Sour - smelling bad" , "No longer fresh" .)