The Collaborative International Dictionary of English v.0.48:

Blight \Blight\ (bl[imac]t), v. t. [imp. & p. p. Blighted; p.
   pr. & vb. n. Blighting.] [Perh. contr. from AS.
   bl[imac]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.
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            [This vapor] blasts vegetables, blights corn and
            fruit, and is sometimes injurious even to man.
                                                  --Woodward.
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   2. Hence: To destroy the happiness of; to ruin; to mar
      essentially; to frustrate; as, to blight one's prospects.
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            Seared in heart and lone and blighted. --Byron.
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The Collaborative International Dictionary of English v.0.48:

Blighting \Blight"ing\, a.
   Causing blight.
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