Rubbish art mixed up with old Turner (7)
I believe the answer is:
rotator
'turner' is the definition.
(I've seen this in another clue)
'rubbish art mixed up with old' is the wordplay.
'rubbish' becomes 'rot' (both can mean nonsense).
'mixed up with' indicates an anagram.
'old' becomes 'o' (abbreviation).
'art' with its letters mixed up with 'o' makes 'ator'.
'rot'+'ator'='ROTATOR'
(Other definitions for rotator that I've seen before include "One goes round" , "Something that turns" , "Device that spins" , "Something turning" , "Muscle that turns" .)