de- pref. meaning (1) down (depend, descend), away (defend, deduct), removal (decapitate), completely (declare, denude), in a bad sense (deceive, defame, deride); (2) [thro. OF des- f. L dis-] removal or reversal, forming compd. vbs. (w. derivs.) from vbs. (de-acidify, de-centralize, decentralization, de-escalate, demoralize, demoralization, depressurize, desegregate) and ns. (defuse, dehorn, de-ice, delouse, detrain) [f. or after L de adv. & prep. = off, from]