Nauseating (7)
I believe the answer is:
noisome
'nauseating' is the definition.
(I know that nauseating can be written as noisome)
This is all the clue.
(Other definitions for noisome that I've seen before include "Repellent" , "Unpleasantly smelling" , "Evil-smelling, objectionable (7)" , "Harmful - offensive" , "Having an extremely offensive smell" .)