curdling vs natural action

curdling and natural action both are nouns.

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

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

curdling: the process of forming semisolid lumps in a liquid
natural action: a process existing in or produced by nature (rather than by the intent of human beings)

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

curdling (noun)	natural action (noun)
the process of forming semisolid lumps in a liquid	a process existing in or produced by nature (rather than by the intent of human beings)