Rastafarianism vs cultus

Rastafarianism and cultus both are nouns.

Word	Noun	Adjective	Verb	Adverb
Rastafarianism	Yes	No	No	No
cultus	Yes	No	No	No

As nouns, cultus is a hypernym of Rastafarianism; that is, cultus is a word with a broader meaning than Rastafarianism:

Rastafarianism: a religious cult based on a belief that Ras Tafari (Haile Selassie) is the Messiah and that Africa (especially Ethiopia) is the Promised Land
cultus: a system of religious beliefs and rituals

Other hypernyms of Rastafarianism include cult, religious cult.

Rastafarianism (noun)	cultus (noun)
a religious cult based on a belief that Ras Tafari (Haile Selassie) is the Messiah and that Africa (especially Ethiopia) is the Promised Land	a system of religious beliefs and rituals