rising vs acclivitous

rising is a noun but acclivitous is not a noun.

Word	Noun	Adjective	Verb	Adverb
rising	Yes	Yes	No	No
acclivitous	No	Yes	No	No

As adjectives, rising and acclivitous are synonyms defined as:

Other synonyms of rising include uphill.

rising (noun)	acclivitous (noun)
organized opposition to authority; a conflict in which one faction tries to wrest control from another
a movement upward; rise above the ground

rising (adjective)	acclivitous (adjective)
advancing or becoming higher or greater in degree or value or status	sloping upward
sloping upward
coming to maturity
newly come into prominence