Origin: 1250–1300; Middle English eri, dialectal variant of argh,Old English earg cowardly; cognate with Old Frisian erg,Old Norse argr evil, German arg cowardly
c.1300, north England and Scottish variant of O.E. earg "cowardly, fearful," from P.Gmc. *argaz (cf. O.N. argr "unmanly, voluptuous," Swed. arg "malicious," Ger. arg "bad, wicked"). Sense of "causing fear because of strangeness" is first attested 1792. Related: Eerily.