Synonyms for Irritability (same or very similar meaning)
WordNet sense 1 (an irritable petulant feeling):
choler, crossness, fretfulness, fussiness, peevishness, petulanceWordNet sense 2 (excessive sensitivity of an organ or body part):
excitabilityWordNet sense 3 (a disposition to exhibit uncontrolled anger):
biliousness, surliness, temper, pettishness, snappishnessFrom the ODE community, based on WordNetadd/edit