Imitation; impression (13)
I believe the answer is:
impersonation
I believe this clue is a double definition.
'imitation' is the first definition.
(I know that imitation can be written as impersonation)
'impression' is the second definition.
(thesaurus)
(Other definitions for impersonation that I've seen before include "identity theft?" , "Pretence of being another person" , "Mimicry" , "Pretence of being someone else" , "Pretending to be someone else" .)