Source : Webster's Revised Unabridged Dictionary (1913)

Blight \Blight\, v. i.
   To be affected by blight; to blast; as, this vine never
   blights.

Blight \Blight\ (bl[imac]t), v. t. [imp. & p. p. {Blighted}; p.
   pr. & vb. n. {Blighting}.] [Perh. contr. from AS.
   bl[=i]cettan to glitter, fr. the same root as E. bleak. The
   meaning ``to blight'' comes in that case from to glitter,
   hence, to be white or pale, grow pale, make pale, bleach. Cf.
   {Bleach}, {Bleak}.]
   1. To affect with blight; to blast; to prevent the growth and
      fertility of.

            [This vapor] blasts vegetables, blights corn and
            fruit, and is sometimes injurious even to man.
                                                  --Woodward.

   2. Hence: To destroy the happiness of; to ruin; to mar
      essentially; to frustrate; as, to blight one's prospects.

            Seared in heart and lone and blighted. --Byron.

Blight \Blight\, n.
   1. Mildew; decay; anything nipping or blasting; -- applied as
      a general name to various injuries or diseases of plants,
      causing the whole or a part to wither, whether occasioned
      by insects, fungi, or atmospheric influences.

   2. The act of blighting, or the state of being blighted; a
      withering or mildewing, or a stoppage of growth in the
      whole or a part of a plant, etc.

   3. That which frustrates one's plans or withers one's hopes;
      that which impairs or destroys.

            A blight seemed to have fallen over our fortunes.
                                                  --Disraeli.

   4. (Zo["o]l.) A downy species of aphis, or plant louse,
      destructive to fruit trees, infesting both the roots and
      branches; -- also applied to several other injurious
      insects.

   5. pl. A rashlike eruption on the human skin. [U. S.]

Source : WordNet®

blight
     n 1: a state or condition being blighted
     2: any plant disease resulting in withering without rotting
     v : cause to suffer a blight; "Too much rain may blight the
         garden with mold" [syn: {plague}]