The Collaborative International Dictionary of English v.0.48:

Eradicate \E*rad"i*cate\, v. t. [imp. & p. p. Eradicated; p.
   pr. & vb. n. Eradicating.] [L. eradicatus, p. p. of
   eradicare to eradicate; e out + radix, radicis, root. See
   Radical.]
   1. To pluck up by the roots; to root up; as, an oak tree
      eradicated.
      [1913 Webster]

   2. To root out; to destroy utterly; to extirpate; as, to
      eradicate diseases, or errors.
      [1913 Webster]

            This, although now an old an inveterate evil, might
            be eradicated by vigorous treatment.  --Southey.

   Syn: To extirpate; root out; exterminate; destroy;
        annihilate.
        [1913 Webster]

WordNet (r) 3.0 (2006):

eradicate
    v 1: kill in large numbers; "the plague wiped out an entire
         population" [syn: eliminate, annihilate, extinguish,
         eradicate, wipe out, decimate, carry off]
    2: destroy completely, as if down to the roots; "the vestiges of
       political democracy were soon uprooted" "root out corruption"
       [syn: uproot, eradicate, extirpate, root out,
       exterminate]