invariance vs unchangingness

invariance and unchangingness both are nouns.

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

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

invariance: the quality of being resistant to variation
unchangingness: the quality of being unchangeable; having a marked tendency to remain unchanged

Other hypernyms of invariance include changelessness, unchangeability, unchangeableness.

invariance (noun)	unchangingness (noun)
the quality of being resistant to variation	the quality of being unchangeable; having a marked tendency to remain unchanged
the nature of a quantity or property or function that remains unchanged when a given transformation is applied to it