diplomat vs envoy

diplomat and envoy both are nouns.

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

As nouns, envoy is a hyponym of diplomat; that is, envoy is a word with a more specific, narrower meaning than diplomat:

diplomat (noun)	envoy (noun)
an official engaged in international negotiations	a brief stanza concluding certain forms of poetry
a person who deals tactfully with others	a diplomat having less authority than an ambassador
	someone sent on a mission to represent the interests of someone else