Artist wearing an acceptable type of jacket (6)
I believe the answer is:
anorak
'type of jacket' is the definition.
'artist wearing an acceptable' is the wordplay.
'artist' becomes 'RA' (Royal Academician, member of Royal Academy of Arts).
'wearing' indicates putting letters inside.
'acceptable' becomes 'OK' (OK can mean acceptable or fine).
'an'+'ok'='anok'
'ra' placed within 'anok' is 'ANORAK'.
(Other definitions for anorak that I've seen before include "Coat (for the boringly obsessive?)" , "Parka, windcheater" , "Jacket; inept person" , "Socially inept person" , "Jacket for an obsessive?" .)