Synonyms for Irascible (same or very similar meaning)
WordNet sense 1 (quickly aroused to anger):
choleric, hot-tempered, hotheaded, quick-tempered, short-temperedWordNet sense 2 (having an irritable and unpleasant disposition):
ill-naturedWordNet sense 3 (feeling or showing anger):
angryFrom the ODE community, based on WordNetadd/edit