eerie (adj.)
c.1300, "fearful, timid," north England and Scottish variant of Old English earg "cowardly, fearful," from Proto-Germanic *argaz (cognates: Old Frisian erg "evil, bad," Middle Dutch arch "bad," Dutch arg, Old High German arg "cowardly, worthless," German arg "bad, wicked," Old Norse argr "unmanly, voluptuous," Swedish arg "malicious").

Sense of "causing fear because of strangeness" is first attested 1792. Related: Eerily. Finnish arka "cowardly" is a Germanic loan-word.