Emily Dickinson Lexicon

IR'RI-TATE, v.t. [L. irrito; in and ira, wrath; W. irad, pungency, passion, rage; or perhaps more properly from Sw. reta, to provoke; G. reitzen; to tickle, vellicate, irritate.]

1. To excite heat and redness in the skin or flesh of living animal bodies, as by friction; to inflame; to fret; as, to irritate a wounded part by a coarse bandage.
2. To excite anger; to provoke; to tease; to exasperate. Never irritate a child for trifling faults. The insolence of a tyrant irritates his subjects.
3. To increase action or violence; to highten excitement in. Air, if very cold, irritateth the flame. Bacon.
4. To cause fibrous contractions in an extreme part of the sensorium, as by the appulse of an external body. Darwin.