diplomatist vs diplomat

diplomatist and diplomat both are nouns.

Word	Noun	Adjective	Verb	Adverb
diplomatist	Yes	No	No	No
diplomat	Yes	No	No	No

As nouns, diplomatist and diplomat are synonyms defined as:

diplomatist and diplomat: an official engaged in international negotiations

diplomatist (noun)	diplomat (noun)
an official engaged in international negotiations	an official engaged in international negotiations
	a person who deals tactfully with others