communism vs ideology

communism and ideology both are nouns.

Word	Noun	Adjective	Verb	Adverb
communism	Yes	No	No	No
ideology	Yes	No	No	No

As nouns, ideology is a hypernym of communism; that is, ideology is a word with a broader meaning than communism:

communism: a political theory favoring collectivism in a classless society
ideology: an orientation that characterizes the thinking of a group or nation

Other hypernyms of communism include political orientation, political theory.

communism (noun)	ideology (noun)
a political theory favoring collectivism in a classless society	an orientation that characterizes the thinking of a group or nation
a form of socialism that abolishes private ownership	imaginary or visionary theorization