misdeed n.

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).

"that which is done, acted, or performed, whether good or bad, great or small," Old English dæd "a doing, act, action; transaction, event," from Proto-Germanic *dethi- (source also of Old Saxon dad, Old Norse dað, Old Frisian dede, Middle Dutch daet, Dutch daad, Old High German tat, German Tat "deed, thing done," Gothic gadeþs "a putting, placing"), from PIE *dheti- "thing laid down or done; law; deed" (source also of Lithuanian dėtis "load, burden," Greek thesis "a placing, setting"), suffixed form of root *dhe- "to set, place, put" (compare do).

In law, "written document authenticated by seal of the person whose will it declares, especially for the purpose of conveying real estate" is from early 14c. As a verb, "convey or transfer by deed," 1806, American English. Related: Deeded; deeding.