To reverse or erase; annul: impossible to undo the suffering caused by the war.
To untie, disassemble, or loosen: undo a shoelace.
To open (a parcel, for example); unwrap.
To cause the ruin or downfall of; destroy.
To throw into confusion; unsettle.
Obsolete To solve or interpret; unravel.
(ŭn-dōō') 