(1):

(n.) To make morbidly excitable, or oversensitive; to fret; as, the skin is irritated by friction; to irritate a wound by a coarse bandage.

(2):

(v. t.) To produce irritation in; to stimulate; to cause to contract. See Irritation, n., 2.

(3):

(v. t.) To excite anger or displeasure in; to provoke; to tease; to exasperate; to annoy; to vex; as, the insolence of a tyrant irritates his subjects.

(4):

(v. t.) To render null and void.

(5):

(a.) Excited; heightened.

(6):

(v. t.) To increase the action or violence of; to heighten excitement in; to intensify; to stimulate.