ir·ri·ta·ble 
(ĭrĭ-tə-bəl)
(ĭrĭ-tə-bəl)adj.
1. Easily irritated or annoyed.
2. Medicine Abnormally or excessively sensitive to a stimulus: irritable bladder.
3. Capable of responding to a stimulus. Used of an organism.
[French irritable, from Latin irrītābilis, from irrītāre, to irritate.]
ir′ri·ta·bili·ty (-bĭlĭ-tē), irri·ta·ble·ness n.
irri·ta·bly adv.