stability vs unchangeability

stability and unchangeability both are nouns.

Word	Noun	Adjective	Verb	Adverb
stability	Yes	No	No	No
unchangeability	Yes	No	No	No

As nouns, unchangeability is a hypernym of stability; that is, unchangeability is a word with a broader meaning than stability:

stability: the quality of being enduring and free from change or variation
unchangeability: the quality of being unchangeable; having a marked tendency to remain unchanged

Other hypernyms of stability include changelessness, unchangeableness, unchangingness.

stability (noun)	unchangeability (noun)
the quality or attribute of being firm and steadfast	the quality of being unchangeable; having a marked tendency to remain unchanged
the quality of being enduring and free from change or variation
a stable order (especially of society)