communist vs Bolshevik

communist and Bolshevik both are nouns.

Word	Noun	Adjective	Verb	Adverb
communist	Yes	Yes	No	No
Bolshevik	Yes	Yes	No	No

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

communist: a socialist who advocates communism
Bolshevik: a Russian member of the left-wing majority group that followed Lenin and eventually became the Russian communist party

Other hyponyms of communist include apparatchik, Bolshevist, Comrade, revisionist.

communist (noun)	Bolshevik (noun)
a socialist who advocates communism	emotionally charged terms used to refer to extreme radicals or revolutionaries
	a Russian member of the left-wing majority group that followed Lenin and eventually became the Russian communist party

communist (adjective)	Bolshevik (adjective)
relating to or marked by communism	of or relating to Bolshevism