Lifeless, occasionally dour, dirty place (5)
I believe the answer is:
dusty
'lifeless' is the definition.
(thesaurus)
'occasionally dour dirty place' is the wordplay.
'occasionally' means one should take alternating letters.
'dirty place' becomes 'sty' (I've seen this in other clues).
The alternate letters of 'dour' are 'du'.
'du'+'sty'='DUSTY'
(Other definitions for dusty that I've seen before include "pale" , "Boring" , "In need of cleaning" , "bad?" , "Ms Springfield" .)