The Collaborative International Dictionary of English v.0.48:

Destructive \De*struc"tive\, a. [L. destructivus: cf. F.
   destructif.]
   Causing destruction; tending to bring about ruin, death, or
   devastation; ruinous; fatal; productive of serious evil;
   mischievous; pernicious; -- often with of or to; as,
   intemperance is destructive of health; evil examples are
   destructive to the morals of youth.
   [1913 Webster]

         Time's destructive power.                --Wordsworth.
   [1913 Webster]

   Destructive distillation. See Distillation.

   Destructive sorties(Logic), a process of reasoning which
      involves the denial of the first of a series of dependent
      propositions as a consequence of the denial of the last; a
      species of reductio ad absurdum. --Whately.

   Syn: Mortal; deadly; poisonous; fatal; ruinous; malignant;
        baleful; pernicious; mischievous.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Destructive \De*struc"tive\, n.
   One who destroys; a radical reformer; a destructionist.
   [1913 Webster]

WordNet (r) 3.0 (2006):

destructive
    adj 1: causing destruction or much damage; "a policy that is
           destructive to the economy"; "destructive criticism"
           [ant: constructive]