Dirty, untidy (5)
I believe the answer is:
messy
This clue is a double definition.
'dirty' is the first definition.
(messy can mean dirty or grimy)
'untidy' is the second definition.
(synonyms)
(Other definitions for messy that I've seen before include "Dirty and disorderly" , "Untidy, dirty" , "Disorganised" .)