Absent-minded don, not working, is characteristic (8)
I believe the answer is:
distrait
'absent-minded' is the definition.
(thesaurus)
'don not working is characteristic' is the wordplay.
'not' suggests deleting specific letters.
'working' becomes 'on'.
'characteristic' becomes 'trait' (I've seen this before).
'don' with 'on' removed is 'd'.
'd'+'is'+'trait'='DISTRAIT'
(Other definitions for distrait that I've seen before include "Being one [SCATTY]" , "Distraught in France" , "Preoccupied" , "Unable to concentrate for anxiety - it is trad (anag)" , "Inattentive or absent-minded, from French" .)