imitator vs actor

imitator and actor both are nouns.

Word	Noun	Adjective	Verb	Adverb
imitator	Yes	No	No	No
actor	Yes	No	No	No

As nouns, actor is a hypernym of imitator; that is, actor is a word with a broader meaning than imitator:

Other hypernyms of imitator include doer, worker.

imitator (noun)	actor (noun)
someone who copies the words or behavior of another	a theatrical performer
someone who (fraudulently) assumes the appearance of another	a person who acts and gets things done