copycat vs imitator

copycat and imitator both are nouns.

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

As nouns, copycat and imitator are synonyms defined as:

copycat and imitator: someone who copies the words or behavior of another

Other synonyms of copycat include ape, aper, emulator.

copycat (noun)	imitator (noun)
someone who copies the words or behavior of another	someone who copies the words or behavior of another
	someone who (fraudulently) assumes the appearance of another