1154, wil "wile, trick," perhaps from O.N.Fr. *wile (O.Fr. guile), or directly from a Scand. source (cf. O.N. vel "trick, craft, fraud," vela "defraud"). Perhaps ultimately related to O.E. wicca "wizard" (see Wicca). Lighter sense of "amorous or playful trick" is from 1600. Wily is attested from c.1300.