Not as dirty (7)
I believe the answer is:
cleaner
'not as dirty' is the definition.
('clean' can be the opposite of 'dirty' so perhaps 'cleaner' is reasonable for 'not as dirty')
This is all the clue.
(Other definitions for cleaner that I've seen before include "More hygienic" , "Daily help" , "Less soiled" , "Eg, launderer, duster" , "Maybe Daily" .)