Artist's impression of tragedians sacrificing a rat (6)
I believe the answer is:
design
'artist's' is the definition.
(thesaurus)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for design that I've seen before include "Plan, blueprint" , "Devise, create, make out a plan" , "Plan, drawing" , "Prepare a plan for something to be made" , "Preliminary sketch or plan" .)