irritability vs excitability

irritability and excitability both are nouns.

Word	Noun	Adjective	Verb	Adverb
irritability	Yes	No	No	No
excitability	Yes	No	No	No

As nouns, irritability and excitability are synonyms defined as:

irritability and excitability: excessive sensitivity of an organ or body part

irritability (noun)	excitability (noun)
a disposition to exhibit uncontrolled anger	being easily excited
excessive sensitivity of an organ or body part	excessive sensitivity of an organ or body part
an irritable petulant feeling