Expressions used in Everyday Spoken English in Social and Professional contexts
'To impersonate' someone means to pretend to be them. You could impersonate a famous celebrity or politician in order to entertain your friends or you might try to impersonate someone in order to trick someone or to commit a crime, such as fraud. A less formal phrase that means the same thing is 'to take off someone'. You can hear this used in social and professional contexts.