instability vs disorder

instability and disorder both are nouns.

Word	Noun	Adjective	Verb	Adverb
instability	Yes	No	No	No
disorder	Yes	No	Yes	No

As nouns, disorder is a hypernym of instability; that is, disorder is a word with a broader meaning than instability:

instability (noun)	disorder (noun)
the quality or attribute of being unstable and irresolute	a disturbance of the peace or of public order
unreliability attributable to being unstable	a condition in which things are not in their expected places
an unstable order	a physical condition in which there is a disturbance of normal functioning
a lack of balance or state of disequilibrium

instability (verb)	disorder (verb)
	bring disorder to
	disturb in mind or make uneasy or cause to be worried or alarmed