misjudge v.

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).

c. 1200, iugen, "examine, appraise, make a diagnosis;" c. 1300, "to form an opinion about; inflict penalty upon, punish; try (someone) and pronounce sentence," also intransitive, "make a decision, decide, think, suppose;" from Anglo-French juger, Old French jugier "to judge, pronounce judgment; pass an opinion on" (10c., Modern French juger), from Latin iudicare "to judge, to examine officially; form an opinion upon; pronounce judgment," from iudicem (nominative iudex) "a judge," a compound of ius "right, law" (see just (adj.)) + root of dicere "to say" (from PIE root *deik- "to show," also "pronounce solemnly").

Related: Judged; judging. Spelling with -dg- emerged mid-15c. The Old English word was deman (see doom (n.)). The Latin word also is the source of Spanish juzgar, Italian giudicare.