Stink; buzz (3)
I believe the answer is:
hum
I believe this is a double definition.
'stink' is the first definition.
(I've seen this in other cluesasomething with a bad)
'buzz' is the second definition.
(I know that buzz can be written as hum)
(Other definitions for hum that I've seen before include "Sing with the mouth shut" , "Reek" , "Low sound of bad smell?" , "Buzz; stink" , "Make musical sound with closed lips" .)