impostor vs imposter

impostor and imposter both are nouns.

Word	Noun	Adjective	Verb	Adverb
impostor	Yes	No	No	No
imposter	Yes	No	No	No

As nouns, impostor and imposter are synonyms defined as:

Other synonyms of impostor include fake, faker, fraud, pretender, pseud, pseudo, role player, sham, shammer.

impostor (noun)	imposter (noun)
a person who makes deceitful pretenses	a person who makes deceitful pretenses