Italian word comunismo comes from French -isme (-ism.)

Detailed word origin of comunismo

Dictionary entry	Language	Definition
-isme	French (fra)	-ism.
commun	French (fra)	Common (of low class). Common (popular). Common (widespread). Communal.
communisme	French (fra)	(commonly) The Marxist ideology communism. (literally) Any collectivism.
comunismo	Italian (ita)	(philosophy) communism. (politics) Communism.