demonstrator vs meliorist

demonstrator and meliorist both are nouns.

Word	Noun	Adjective	Verb	Adverb
demonstrator	Yes	No	No	No
meliorist	Yes	No	No	No

As nouns, meliorist is a hypernym of demonstrator; that is, meliorist is a word with a broader meaning than demonstrator:

Other hypernyms of demonstrator include crusader, reformer, reformist, social reformer.

demonstrator (noun)	meliorist (noun)
someone who participates in a public display of group feeling	a disputant who advocates reform
someone who demonstrates an article to a prospective buyer
a teacher or teacher's assistant who demonstrates the principles that are being taught