variable vs variability

variable and variability both are nouns.

Word	Noun	Adjective	Verb	Adverb
variable	Yes	Yes	No	No
variability	Yes	No	No	No

variable (noun)	variability (noun)
a quantity that can assume any of a set of values	the quality of being subject to variation
a symbol (like x or y) that is used in mathematical or logical expressions to represent a variable quantity	the quality of being uneven and lacking uniformity
something that is likely to vary; something that is subject to variation
a star that varies noticeably in brightness

variable (adjective)	variability (adjective)
liable to or capable of change
(used of a device) designed so that a property (as e.g. light) can be varied
marked by diversity or difference