Available Definitions:
1) v. t. - To render null and void.
2) v. t. - To increase the action or violence of; to heighten excitement in; to intensify; to stimulate.
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 produce irritation in; to stimulate; to cause to contract. See Irritation , n., 2.
5) n. - To make morbidly excitable, or oversensitive; to fret; as, the skin is irritated by friction; to irritate a wound by a coarse bandage.
6) a. - Excited; heightened.