1530s, "stimulate to action, rouse, incite," from Latin irritatus, past participle of irritare "excite, provoke, annoy;" according to de Vaan, probably a verb from Proto-Italic *rito- "stirred," from the same PIE root that produced English run (v.). Meaning "annoy, make impatient" in English is from 1590s. The earlier verb in English was irrite (mid-15c.), from Old French irriter. Related: Irritated; irritating.

1630s, from Latin irritantem (nominative irritans), present participle of irritare "to excite, provoke" (see irritate). As a noun, "that which irritates," from 1802.

"that causes annoyance," 1707, present-participle adjective from irritate (v.). Related: Irritatingly. Earlier adjective forms were irritative (1680s), irritatory (1650s).

1660s, "susceptible to mental irritation," from French irritable and directly from Latin irritabilis "easily excited," from irritare "excite, provoke" (see irritate). Meaning "responding quickly to a stimulus" is from 1791. Related: Irritably.

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.

1530s, "irritate, provoke to anger," from Latin exasperatus, past participle of exasperare "make rough, roughen, irritate, provoke," from ex "out, out of; thoroughly" (see ex-) + asper "rough" (see asperity). Related: Exasperated; exasperating.

c. 1400, "to vex, irritate," probably a back-formation from crabbed. The notions of "bad-tempered, combative" and "sour" in the two nouns crab naturally yielded a verb meaning of "to vex, irritate," later "to complain irritably, find fault" (c. 1500). As "to fish for crabs" from 1650s (implied in crabbing). The noun meaning "sour person" is from 1570s.

"irritation, provocation," 1540s, from Late Latin exasperationem (nominative exasperatio), noun of action from past-participle stem of exasperare "roughen; irritate" (see exasperate).

"to annoy, irritate," 1949, perhaps first in swing music slang, probably from bug (n.) and a reference to insect pests. Related: Bugged; bugging.

"irritate, exasperate," 1907 (implied in peeved), back-formation from peevish. Also "to grumble, complain" (1912). As a noun, attested by 1910. Related: Peeved; peeving; peeves.