softening vs natural action

softening and natural action both are nouns.

Word	Noun	Adjective	Verb	Adverb
softening	Yes	Yes	No	No
natural action	Yes	No	No	No

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

softening: the process of becoming softer
natural action: a process existing in or produced by nature (rather than by the intent of human beings)

Other hypernyms of softening include action, activity, natural process.

softening (noun)	natural action (noun)
the process of becoming softer	a process existing in or produced by nature (rather than by the intent of human beings)

softening (adjective)	natural action (adjective)
having a softening or soothing effect especially to the skin