fraud vs impostor

fraud and impostor both are nouns.

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

As nouns, fraud and impostor are synonyms defined as:

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

fraud (noun)	impostor (noun)
intentional deception resulting in injury to another person	a person who makes deceitful pretenses
something intended to deceive; deliberate trickery intended to gain an advantage
the act of swindling by some fraudulent scheme
a person who makes deceitful pretenses