Artist gave terrible harm (6)
I believe the answer is:
ravage
'harm' is the definition.
Although both the answer and definition are verbs in their base form, I cannot see how they can define each other.
'artist gave terrible' is the wordplay.
'artist' becomes 'RA' (Royal Academician, member of Royal Academy of Arts).
'terrible' indicates anagramming the letters.
'gave' with letters rearranged gives 'vage'.
'ra'+'vage'='RAVAGE'
Can you help me to learn more?
(Other definitions for ravage that I've seen before include "Lay waste, plunder" , "Greatly damage, destroy" , "Pillage or lay waste" , "Wreak havoc upon" , "Act like a 6" .)