vitiate \vi"tiate\, v. t. imp.  p. p. vitiated; p. pr. 
   vb. n. vitiating. l. vitiatus, p. p. vitiare to vitiate,
   fr. vitium a fault, vice. see vice a fault. written also
   viciate.
   1. to make vicious, faulty, or imperfect; to render
      defective; to injure the substance or qualities of; to
      impair; to contaminate; to spoil; as, exaggeration
      vitiates a style of writing; sewer gas vitiates the air.
      1913 webster

            a will vitiated and growth out of love with the
            truth disposes the understanding to error and
            delusion.                             --south.
      1913 webster

            without care it may be used to vitiate our minds.
                                                  --burke.
      1913 webster

            this undistinguishing complaisance will vitiate the
            taste of readers.                     --garth.
      1913 webster

   2. to cause to fail of effect, either wholly or in part; to
      make void; to destroy, as the validity or binding force of
      an instrument or transaction; to annul; as, any undue
      influence exerted on a jury vitiates their verdict; fraud
      vitiates a contract.
      1913 webster
see also:
vitiated vitiating vice viciate