Slovenly, foul (7)
I believe the answer is:
squalid
I believe this clue is a double definition.
'slovenly' is the first definition.
(thesaurus)
'foul' is the second definition.
(both can mean disgusting)
(Other definitions for squalid that I've seen before include "Seamy, sleazy" , "Run-down - filthy" , "Foul" , "Dirty and repulsive" , "Slum-like" .)