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 ]