Dusty, untidy room? (5)
I believe the answer is:
study
'room?' is the definition.
(I know that study is a room)
'dusty untidy' is the wordplay.
'untidy' is an anagram indicator.
'dusty' anagrammed gives 'STUDY'.
(Other definitions for study that I've seen before include "See 11" , "Scrutinize" , "Contemplate" , "Read to learn" , "Swot" .)