what do you call a person that's good at acting like someone else

Answer 1

A person who is good at acting like someone else is often referred to as an "impersonator." If they specialize in theatrical performances, they might also be called an "actor" or "performer." If their skills involve mimicry or imitation of someone's mannerisms, they could be referred to as a "mimic." In some contexts, particularly in comedy, they may be known as a "spoof artist" or "satirist."