rigidifying vs natural process

rigidifying and natural process both are nouns.

Word	Noun	Adjective	Verb	Adverb
rigidifying	Yes	No	No	No
natural process	Yes	No	No	No

As nouns, natural process is a hypernym of rigidifying; that is, natural process is a word with a broader meaning than rigidifying:

rigidifying: the process of becoming stiff or rigid
natural process: a process existing in or produced by nature (rather than by the intent of human beings)

Other hypernyms of rigidifying include action, activity, natural action.

rigidifying (noun)	natural process (noun)
the process of becoming stiff or rigid	a process existing in or produced by nature (rather than by the intent of human beings)