a. Excited; heightened. [ Obs. ] [ 1913 Webster ]

v. t. [ imp. & p. p. Irritated p. pr. & vb. n. Irritating ] [ L. irritatus, p. p. of irritare. Of doubtful origin. ] [ 1913 Webster ]

1. To increase the action or violence of; to heighten excitement in; to intensify; to stimulate. [ 1913 Webster ]

Cold maketh the spirits vigorous and irritateth them. Bacon. [ 1913 Webster ]

2. 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. [ 1913 Webster ]

Dismiss the man, nor irritate the god:
Prevent the rage of him who reigns above. Pope. [ 1913 Webster ]

3. (Physiol.) To produce irritation in; to stimulate; to cause to contract. See Irritation, n., 2. [ 1913 Webster ]

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

Syn. -- To fret; inflame; excite; provoke; tease; vex; exasperate; anger; incense; enrage. -- To Irritate, Provoke, Exasperate. These words express different stages of excited or angry feeling. Irritate denotes an excitement of quick and slightly angry feeling which is only momentary; as, irritated by a hasty remark. To provoke implies the awakening of some open expression of decided anger; as, a provoking insult. Exasperate denotes a provoking of anger at something unendurable. Whatever comes across our feelings irritates; whatever excites anger provokes; whatever raises anger to a high point exasperates. “Susceptible and nervous people are most easily irritated; proud people are quickly provoked; hot and fiery people are soonest exasperated.” Crabb. [ 1913 Webster ]

v. t. [ See 1 st Irritant. ] To render null and void. [ R. ] Abp. Bramhall. [ 1913 Webster ]

adj. aroused to impatience or anger; as, made an irritated gesture.
Syn. -- annoyed, nettled, peeved, pissed, stung. [ WordNet 1.5 ]

adj. 1. causing annoyance.
Syn. -- annoying, galling, chafing, nettlesome, pesky, pestiferous, pestilent, plaguy, plaguey, teasing, vexatious, vexing. [ WordNet 1.5 +PJC ]

2. causing irritation of living tissue; -- used of physical stimuli.
Syn. -- irritant, irritative. [ WordNet 1.5 +PJC ]

3. causing pain or physical discomfort; as, an irritating burr under his stocking.
Syn. -- painful. [ WordNet 1.5 ]

n. [ L. irritatio: cf. F. irritation. ] [ 1913 Webster ]

1. The act of irritating, or exciting, or the state of being irritated; excitement; stimulation, usually of an undue and uncomfortable kind; especially, excitement of anger or passion; provocation; annoyance; anger. [ 1913 Webster ]

The whole body of the arts and sciences composes one vast machinery for the irritation and development of the human intellect. De Quincey. [ 1913 Webster ]

2. (Physiol.) The act of exciting, or the condition of being excited to action, by stimulation; -- as, the condition of an organ of sense, when its nerve is affected by some external body; esp., the act of exciting muscle fibers to contraction, by artificial stimulation; as, the irritation of a motor nerve by electricity; also, the condition of a muscle and nerve, under such stimulation. [ 1913 Webster ]

3. (Med.) A condition of morbid excitability or oversensitiveness of an organ or part of the body; a state in which the application of ordinary stimuli produces pain or excessive or vitiated action. [ 1913 Webster ]

a. 1. Serving to excite or irritate; irritating; as, an irritative agent. [ 1913 Webster ]

2. Accompanied with, or produced by, increased action or irritation; as, an irritative fever. E. Darwin. [ 1913 Webster ]

a. Exciting; producing irritation; irritating. [ R. ] Hales. [ 1913 Webster ]