prefix meaning "bad, wrong," from O.E. mis-, from P.Gmc. *missa- "divergent, astray" (cf. O.Fris. mis-, M.Du. misse-, O.H.G. missa-, Ger. miß-, O.N. mis-, Goth. missa-), perhaps with a root sense of "difference, change" (cf. Goth. misso "mutually"), and thus from PIE *mit-to-, from base *mei- "to change" (see mutable). Others see in P.Gmc. *missa- the stem of an ancient pp., related to O.E. missan "fail to hit" (see miss (v.)), which is from the same PIE base. Used both with sense of "incorrect" (mistake) and "bad" (mishap); in 14c.-16c. in a few verbs it began to be felt as "unfavorably" and was used as an intensive prefix with verbs already expressing negative feeling (e.g. misdoubt). Practically a separate word in O.E. and early M.E. (and often written as such). O.E. had an adj. (mislic "diverse, unlike, various") and an adv. (mislice "in various directions, wrongly, astray") derived from it, corresponding to Ger. misslich (adj.).

in a handful of words (mischief, miscreant, etc.) represents O.Fr. mes- "bad(ly), wrong(ly)," from V.L. minus-, from L. minus "less," which was not used as a prefix. Perhaps infl. on O.Fr. by the Frank. equivalent of mis- (1).