Word Origin & History
O.E. mist "dimness, mist" (earliest in compounds, such as misthleoðu "misty cliffs," wælmist "mist of death"), from P.Gmc. *mikhstaz (cf. M.L.G. mist, Icelandic mistur), from PIE *migh-/*meigh- (cf. Gk. omikhle, O.C.S. migla, Skt. mih, megha "cloud, mist").
"Sometimes distinguished from fog, either as being less opaque or as consisting of drops large enough to have a perceptible downward motion." [O.E.D.]
Also in O.E. in sense of "dimness of the eyes, either by illness or tears," and in fig. sense of "things that obscure mental vision." The verb is O.E. mistian. Misty is O.E. mistig.