Dirty job without a point (5)
I believe the answer is:
dusty
'dirty' is the definition.
(similar in meaning)
'job without a point' is the wordplay.
'job' becomes 'duty'.
'without' is an insertion indicator ('without' can be similar in meaning to 'outside').
'a point' becomes 'S' (South).
'duty' placed around 's' is 'DUSTY'.
(Other definitions for dusty that I've seen before include "Needing cleaning" , "In need of a spring clean" , "Dull (like a miller?)" , "Boring" , "Dirty" .)