Irritability

n.	1.
	1.	The state or quality of being irritable; quick excitability; petulance; fretfulness; as, irritability of temper.
	2.	(Physiol.) A natural susceptibility, characteristic of all living organisms, tissues, and cells, to the influence of certain stimuli, response being manifested in a variety of ways, - as that quality in plants by which they exhibit motion under suitable stimulation; esp., the property which living muscle possesses, of responding either to a direct stimulus of its substance, or to the stimulating influence of its nerve fibers, the response being indicated by a change of form, or contraction; contractility.
	3.	(Med.) A condition of morbid excitability of an organ or part of the body; undue susceptibility to the influence of stimuli. See Irritation, n., 3.

Noun	1.	irritability - an irritable petulant feeling Synonyms: choler, crossness, fretfulness, fussiness, peevishness, petulance
	2.	irritability - excessive sensitivity of an organ or body part Synonyms: excitability
	3.	irritability - a disposition to exhibit uncontrolled anger; "his temper was well known to all his employees" Synonyms: pettishness, snappishness, surliness, biliousness, peevishness, temper

choler, crossness, distemper, fretfulness, fussiness, ill humor, ill humour, peevishness, pet, petulance, testiness, tetchiness, touchiness