The Collaborative International Dictionary of English v.0.48:

Adulterate \A*dul"ter*ate\, v. t. [imp. & p. p. Adulterated;
   p. pr. & vb. n. Adulterating.] [L. adulteratus, p. p. of
   adulterare, fr. adulter adulterer, prob. fr. ad + alter
   other, properly one who approaches another on account of
   unlawful love. Cf. Advoutry.]
   [1913 Webster]
   1. To defile by adultery. [Obs.] --Milton.
      [1913 Webster]

   2. To corrupt, debase, or make impure by an admixture of a
      foreign or a baser substance; as, to adulterate food,
      drink, drugs, coin, etc.
      [1913 Webster]

            The present war has . . . adulterated our tongue
            with strange words.                   --Spectator.
      [1913 Webster]

   Syn: To corrupt; defile; debase; contaminate; vitiate;
        sophisticate.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Adulterate \A*dul"ter*ate\, v. i.
   To commit adultery. [Obs.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Adulterate \A*dul"ter*ate\, a.
   1. Tainted with adultery.
      [1913 Webster]

   2. Debased by the admixture of a foreign substance;
      adulterated; spurious.
      [1913 Webster] -- A*dul"ter*ate*ly, adv. --
      A*dul"ter*ate*ness, n.
      [1913 Webster]

WordNet (r) 3.0 (2006):

adulterate
    adj 1: mixed with impurities [syn: adulterate, adulterated,
           debased]
    v 1: corrupt, debase, or make impure by adding a foreign or
         inferior substance; often by replacing valuable ingredients
         with inferior ones; "adulterate liquor" [syn: load,
         adulterate, stretch, dilute, debase]