The Collaborative International Dictionary of English v.0.48:

Wilt \Wilt\,
   2d pers. sing. of Will.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Wilt \Wilt\, v. i. [imp. & p. p. Wilting.] [Written also welt,
   a modification of welk.]
   To begin to wither; to lose freshness and become flaccid, as
   a plant when exposed when exposed to drought, or to great
   heat in a dry day, or when separated from its root; to
   droop;. to wither. [Prov. Eng. & U. S.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Wilt \Wilt\, v. t.
   1. To cause to begin to wither; to make flaccid, as a green
      plant. [Prov. Eng. U. S.]
      [1913 Webster]

   2. Hence, to cause to languish; to depress or destroy the
      vigor and energy of. [Prov. Eng. & U. S.]
      [1913 Webster]

            Despots have wilted the human race into sloth and
            imbecility.                           --Dr. T.
                                                  Dwight.
      [1913 Webster]

WordNet (r) 3.0 (2006):

wilt
    n 1: any plant disease characterized by drooping and shriveling;
         usually caused by parasites attacking the roots [syn:
         wilt, wilt disease]
    2: causing to become limp or drooping [syn: wilt, wilting]
    v 1: lose strength; "My opponent was wilting"
    2: become limp; "The flowers wilted" [syn: wilt, droop]