Available Definitions:
1) a. - Capable of being irriated.
2) a. - Very susceptible of anger or passion; easily inflamed or exasperated; as, an irritable temper.
3) a. - Endowed with irritability; susceptible of irritation; capable of being excited to action by the application of certain stimuli.
4) a. - Susceptible of irritation; unduly sensitive to irritants or stimuli. See Irritation , n., 3.