irritation (n.)

early 15c., irritacioun, in physiology, in reference to sores and morbid swelling, from Old French irritacion or directly from Latin irritationem (nominative irritatio) "incitement, stimulus; irritation, wrath, anger," noun of action from past-participle stem of irritare "to excite, provoke" (see irritate). Meaning "impatient or angry excitement" is from 1703.