rigidity vs unadaptability

rigidity and unadaptability both are nouns.

Word	Noun	Adjective	Verb	Adverb
rigidity	Yes	No	No	No
unadaptability	Yes	No	No	No

As nouns, unadaptability is a hypernym of rigidity; that is, unadaptability is a word with a broader meaning than rigidity:

rigidity: the quality of being rigid and rigorously severe
unadaptability: the inability to change or be changed to fit changed circumstances

rigidity (noun)	unadaptability (noun)
the physical property of being stiff and resisting bending	the inability to change or be changed to fit changed circumstances
the quality of being rigid and rigorously severe