imposter vs impostor

imposter and impostor both are nouns.

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

As nouns, imposter and impostor are synonyms defined as:

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

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