Definition of "undo" []

• To reverse or erase; annul: impossible to undo the suffering caused by the war. (verb-transitive)
• To untie, disassemble, or loosen: undo a shoelace. (verb-transitive)
• To open (a parcel, for example); unwrap. (verb-transitive)
• To cause the ruin or downfall of; destroy. (verb-transitive)
• To throw into confusion; unsettle. (verb-transitive)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Leaving your parents out of your lives can result in undo stress, as then you will have to deal with their protests or their anquish over you."
• "Mandela added that economic development would, however, in the longer term undo the socio-economic conditions responsible for a large part of the problem of crime."
• "Yet he realized that were Henry to be entrusted with the regency he would change in the most radical fashion the course of the ship of state; would introduce measures dear to the late Emperor Frederick, but to which he, the kaiser, was unalterably opposed, and would, in short, undo everything that he himself had done; so that when eventually the crown prince came of age there would be no longer any possibility of his continuing his father's policy, a policy which the emperor has been at great pains to inculcate into his boy."