Concern worried painter (7)
I believe the answer is:
pertain
'concern' is the definition.
('pertain' can be a synonym of 'concern')
'worried painter' is the wordplay.
'worried' is an anagram indicator.
'painter' anagrammed gives 'PERTAIN'.
(Other definitions for pertain that I've seen before include "Be related or applicable (to something)" , "Painter (anag) - relate (to)" , "Have relevance" , "Refer" , "Relate (to), apply (to)" .)