Meaning

verb cancel, annul, or reverse an action or its effect

verb deprive of certain characteristics

verb cause the ruin or downfall of

originFrom Middle English undon, from Old English ondōn, from Proto-Germanic *andadōnaz, past participle of *andadōną (“to undo”), equivalent to undo + -en (past participle ending). Cognate with Dutch ontdaan (“stripped, undone, upset”).

Etymology from Wiktionary, CC BY-SA 3.0