'Irritability' definitions:

Definition of 'irritability'

From: WordNet
noun
An irritable petulant feeling [syn: irritability, crossness, fretfulness, fussiness, peevishness, petulance, choler]
noun
Excessive sensitivity of an organ or body part [syn: excitability, irritability]
noun
A disposition to exhibit uncontrolled anger; "his temper was well known to all his employees" [syn: temper, biliousness, irritability, peevishness, pettishness, snappishness, surliness]

Definition of 'Irritability'

From: GCIDE
  • Irritability \Ir`ri*ta*bil"i*ty\, n. [L. irritabilitas: cf. F. irritabilit['e].] [1913 Webster]
  • 1. The state or quality of being irritable; quick excitability; petulance; fretfulness; as, irritability of temper. [1913 Webster]
  • 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. [1913 Webster]
  • 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. [1913 Webster]