Roget's 21st Century Thesaurus, Third Edition Copyright © 2013 by the Philip Lief Group.

WORD ORIGIN

Old English undon "to unfasten and open" (a window or door), "to unfasten by releasing from a fixed position," from un- (2) + do (v.). The notion is of "to annul something that was done." Related: Undone; undoing.

Roget's 21st Century Thesaurus, Third Edition Copyright © 2013 by the Philip Lief Group.