1. Prone to anger; easily provoked to anger; hot-tempered.
The lawyer described his client as an irascible eighty-two-year-old eccentric who alternated between spinning fascinating tales about her past and cussing him out.
— Jack Olsen, Hastened to the Grave
Irascible is from Latin irascibilis, “prone to anger,” from ira, “anger,” which is also the source of ire and irate.