Response about something done (8)
I believe the answer is:
reaction
'response' is the definition.
(synonyms)
'about something done' is the wordplay.
'about' becomes 're' ('re' means regarding or about).
'something done' becomes 'action' (I've seen this before).
're'+'action'='REACTION'
(Other definitions for reaction that I've seen before include "Response to stimulus from creation" , "Chemical change or response" , "Chemical change or backlash" , "In mechanics, every action has an equal and opposite one" , "Creation found in response to event" .)