Awful person staining cloth, by the sound of it (4)
I believe the answer is:
dire
'awful' is the definition.
('dire' can be a synonym of 'awful')
'person staining cloth by the sound of it' is the wordplay.
'person staining cloth' becomes 'dyer' (someone who dyes).
'by the sound of it' shows a homophone (sound like).
'dyer' is a homophone of 'DIRE'.
(Other definitions for dire that I've seen before include "'Dreadful, terrible (4)'" , "Really awful kind of ride" , "Nearly hopeless" , "Disastrous" , "Desperate; dreadful" .)