Seamy (6)
I believe the answer is:
sordid
'seamy' is the definition.
(I know that seamy can be written as sordid)
This is all the clue.
(Other definitions for sordid that I've seen before include "Dirty, depressing and squalid" , "Dirty and unpleasant" , "Squalid or ignorable" , "Squalid, revolting" , "'Seamy, seedy (6)'" .)