vitiate
     v 1: corrupt morally or by intemperance or sensuality; "debauch
          the young people with wine and women"; "Socrates was
          accused of corrupting young men"; "Do school counselors
          subvert young children?"; "corrupt the morals" [syn: {corrupt},
           {pervert}, {subvert}, {demoralize}, {demoralise}, {debauch},
           {debase}, {profane}, {deprave}, {misdirect}]
     2: make imperfect; "nothing marred her beauty" [syn: {mar}, {impair},
         {spoil}, {deflower}]
     3: take away the legal force of or render ineffective;
        "invalidateas a contract" [syn: {invalidate}, {void}]
        [ant: {validate}]
Source: WordNet® 2.0