1590s, from earlier adj. meaning "slanting" (c.1500), probably from M.E. aslope (adv.) "on the incline" (late 15c.), from O.E. *aslopen, pp. of aslupan "to slip away," from a- "away" + slupan "to slip" (see
sleeve). The noun is first recorded 1610s, from the verb. Derogatory