immutableness vs unchangingness

immutableness and unchangingness both are nouns.

Word	Noun	Adjective	Verb	Adverb
immutableness	Yes	No	No	No
unchangingness	Yes	No	No	No

As nouns, unchangingness is a hypernym of immutableness; that is, unchangingness is a word with a broader meaning than immutableness:

immutableness: the quality of being incapable of mutation
unchangingness: the quality of being unchangeable; having a marked tendency to remain unchanged

Other hypernyms of immutableness include changelessness, unchangeability, unchangeableness.

immutableness (noun)	unchangingness (noun)
the quality of being incapable of mutation	the quality of being unchangeable; having a marked tendency to remain unchanged