traitor vs treasonist

traitor and treasonist both are nouns.

Word	Noun	Adjective	Verb	Adverb
traitor	Yes	No	No	No
treasonist	Yes	No	No	No

As nouns, traitor and treasonist are synonyms defined as:

traitor and treasonist: someone who betrays his country by committing treason

traitor (noun)	treasonist (noun)
someone who betrays his country by committing treason	someone who betrays his country by committing treason
a person who says one thing and does another