mistranslate (v.)

early 14c., translaten, "remove from one place to another," also "render into another language, turn from one language to another," from Old French translater and directly from Latin translatus "carried over," serving as past participle of transferre "to bring over, carry over" (see transfer), from trans "across, beyond" (see trans-) + lātus "borne, carried" (see oblate (n.)).

Related: Translated; translating. A similar notion is behind the Old English word it replaced, awendan, from wendan "to turn, direct" (see wend).

prefix of Germanic origin affixed to nouns and verbs and meaning "bad, wrong," from Old English mis-, from Proto-Germanic *missa- "divergent, astray" (source also of Old Frisian and Old Saxon mis-, Middle Dutch misse-, Old High German missa-, German miß-, Old Norse mis-, Gothic missa-), perhaps literally "in a changed manner," and with a root sense of "difference, change" (compare Gothic misso "mutually"), and thus possibly from PIE *mit-to-, from root *mei- (1) "to change."

Productive as word-forming element in Old English (as in mislæran "to give bad advice, teach amiss"). In 14c.-16c. in a few verbs its sense began to be felt as "unfavorably," and it came to be used as an intensive prefix with words already expressing negative feeling (as in misdoubt). Practically a separate word in Old and early Middle English (and often written as such). Old English also had an adjective (mislic "diverse, unlike, various") and an adverb (mislice "in various directions, wrongly, astray") derived from it, corresponding to German misslich (adj.). It has become confused with mis- (2).