de-(word root) not, downExamples of words with the root de-: decompress, descentAbused, Confused, & Misused Words by Mary Embree Copyright © 2007, 2013 by Mary Embreede-pref.1. Do or make the opposite of; reverse: decriminalize.2. Remove or remove from: delouse; deoxygenate.3. Out of: deplane; defenestration.4. Reduce; degrade: declass.5. Derived from: deverbative.[Middle English de-, from Old French de- (from Latin d?-, from, off, apart, away, down, out, completely, from d?; see de- in Indo-European roots) or from Old French des-, out, off, apart, away, completely (from Latin dis-, dis-, and Latin d?-).]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.de- prefix forming verbs and verbal derivatives 1. removal of or from something specified: deforest; dethrone. 2. reversal of something: decode; decompose; desegregate. 3. departure from: decamp. [from Latin, from d? (prep) from, away from, out of, etc. In compound words of Latin origin, de- also means away, away from (decease); down (degrade); reversal (detect); removal (defoliate); and is used intensively (devote) and pejoratively (detest)]Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014de- , a prefix, occurring orig. in loanwords from Latin, used to form verbs that denote motion or conveyance down from, away, or off (deflect; descend); reversal or undoing of the effects of an action (deflate); extraction or removal of a thing (decaffeinate); thoroughness or completeness of an action (despoil). [Middle English