The Collaborative International Dictionary of English v.0.48:

Taint \Taint\, v. t. [F. teint, p. p. of teindre to dye, tinge,
   fr. L. tingere, tinctum. See Tinge, and cf. Tint.]
   1. To imbue or impregnate with something extraneous,
      especially with something odious, noxious, or poisonous;
      hence, to corrupt; to infect; to poison; as, putrid
      substance taint the air.
      [1913 Webster]

   2. Fig.: To stain; to sully; to tarnish.
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            His unkindness may defeat my life,
            But never taint my love.              --Shak.
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   Syn: To contaminate; defile; pollute; corrupt; infect;
        disease; vitiate; poison.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Taint \Taint\, n. [Cf. F. atteinte a blow, bit, stroke. See
   Attaint.]
   1. A thrust with a lance, which fails of its intended effect.
      [Obs.]
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            This taint he followed with his sword drawn from a
            silver sheath.                        --Chapman.
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   2. An injury done to a lance in an encounter, without its
      being broken; also, a breaking of a lance in an encounter
      in a dishonorable or unscientific manner. [Obs.]
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The Collaborative International Dictionary of English v.0.48:

Taint \Taint\, v. i.
   1. To be infected or corrupted; to be touched with something
      corrupting.
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            I can not taint with fear.            --Shak.
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   2. To be affected with incipient putrefaction; as, meat soon
      taints in warm weather.
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The Collaborative International Dictionary of English v.0.48:

Taint \Taint\, n.
   1. Tincture; hue; color; tinge. [Obs.]
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   2. Infection; corruption; deprivation.
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            He had inherited from his parents a scrofulous
            taint, which it was beyond the power of medicine to
            remove.                               --Macaulay.
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   3. A blemish on reputation; stain; spot; disgrace.
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The Collaborative International Dictionary of English v.0.48:

Taint \Taint\, v. i. [imp. & p. p. Tainted; p. pr. & vb. n.
   Tainting.]
   To thrust ineffectually with a lance. [Obs.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Taint \Taint\, v. t.
   1. To injure, as a lance, without breaking it; also, to
      break, as a lance, but usually in an unknightly or
      unscientific manner. [Obs.]
      [1913 Webster]

            Do not fear; I have
            A staff to taint, and bravely.        --Massinger.
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   2. To hit or touch lightly, in tilting. [Obs.]
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            They tainted each other on the helms and passed by.
                                                  --Ld. Berners.
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The Collaborative International Dictionary of English v.0.48:

Taint \Taint\, v. t.
   Aphetic form of Attaint.
   [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

taint
    n 1: the state of being contaminated [syn: contamination,
         taint]
    v 1: place under suspicion or cast doubt upon; "sully someone's
         reputation" [syn: defile, sully, corrupt, taint,
         cloud]
    2: contaminate with a disease or microorganism [syn: infect,
       taint] [ant: disinfect]