c.1460, irken "be weary of, be disgusted with;" earlier intrans., "to feel weary" (c.1330). Of uncertain origin, perhaps related to O.N. yrkja "work" (from PIE base *werg- "to work;" see urge (v.)), or M.H.G. erken "to disgust." Modern sense of "annoy" is from 1483. An adj., irk "weary, tired" is attested from c.1300 in northern and midlands writing. Modern adj. irksome "bothersome, burdensome" is recorded from 1513.