Ruined shirt an artist took off (7)
I believe the answer is:
trashed
'ruined' is the definition.
(I've seen this in another clue)
'shirt an artist took off' is the wordplay.
'shirt' becomes 't' (as in a T-shirt).
'an artist' becomes 'RA' (Royal Academician, member of Royal Academy of Arts).
'took off' becomes 'shed' (I've seen this in another clue).
't'+'ra'+'shed'='TRASHED'
(Other definitions for trashed that I've seen before include "completely taken apart" , "Vandalised" , "Criticised" , "Destroyed" .)