rising vs rapid growth

rising and rapid growth both are nouns.

Word	Noun	Adjective	Verb	Adverb
rising	Yes	Yes	No	No
rapid growth	Yes	No	No	No

As nouns, rapid growth is a hyponym of rising; that is, rapid growth is a word with a more specific, narrower meaning than rising:

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

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