adieugood-bye; farewell; the act of leaving: He bade his friends adieu.Not to be confused with:ado ? bustle, fuss; flurry; confusion; turmoil; commotion: much ado about nothingAbused, Confused, & Misused Words by Mary Embree Copyright © 2007, 2013 by Mary Embreea·dieu (?-dyo?o?, ?-do?o?)interj. Used to express farewell.n. pl. a·dieus or a·dieux (?-dyo?oz?, ?-do?oz?) A farewell.[Middle English, from Old French a dieu, (I commend you) to God : a, to (from Latin ad; see ad-) + Dieu, God (from Latin deus; see dyeu- in Indo-European roots).]American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.adieu (??dju?; French adjø) sentence substitute, n, pl adieus or adieux (??dju?z; French adjø) goodbye; farewell[C14: from Old French, from a to + dieu God]Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014a?dieu (??du, ??dyu) interj., n., pl. a?dieus, a?dieux. good-bye; farewell. [1325?75;