bilingualist vs linguist

bilingualist and linguist both are nouns.

Word	Noun	Adjective	Verb	Adverb
bilingualist	Yes	No	No	No
linguist	Yes	No	No	No

As nouns, linguist is a hypernym of bilingualist; that is, linguist is a word with a broader meaning than bilingualist:

Other hypernyms of bilingualist include polyglot.

bilingualist (noun)	linguist (noun)
a person who speaks two languages fluently	a person who speaks more than one language
	a specialist in linguistics