irk (v.) Look up irk at
early 15c., irken, "to trouble (someone), disturb, hinder, annoy;" earlier "be lax, slow, or unwilling (in doing something); be displeased or discontented" (early 14c.); "be weary of, be disgusted with" (c. 1400); of uncertain origin.

Watkins suggests it is related to Old Norse yrkja "work." Middle High German erken "to disgust" also has been suggested. A Middle English adjective, irk, meaning "weary, tired, bored; distressed, troubled; troublesome, annoying," is attested from c. 1300 in Northern and Midlands writing; it is sometimes said to be from the verb, but it is older, and "Middle English Dictionary" says this is probably Celtic, and compares Old Irish arcoat "he injures," erchoat "harm, injury."