The Collaborative International Dictionary of English v.0.48:

Sunder \Sun"der\, v. t.
   To expose to the sun and wind. [Prov. Eng.] --Halliwell.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Sunder \Sun"der\, v. t. [imp. & p. p. Sundered; p. pr. & vb.
   n. Sundering.] [OE. sundren, AS. sundrain (in [=a]sundrain,
   gesundrain), from sundor asunder, separately, apart; akin to
   D. zonder, prep., without, G. sonder separate, as prep.,
   without, sondern but, OHG. suntar separately, Icel. sundr
   asunder, Sw. & Dan. s["o]nder, Goth. sundr[=o] alone,
   separately.]
   To disunite in almost any manner, either by rending, cutting,
   or breaking; to part; to put or keep apart; to separate; to
   divide; to sever; as, to sunder a rope; to sunder a limb; to
   sunder friends.
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         It is sundered from the main land by a sandy plain.
                                                  --Carew.
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The Collaborative International Dictionary of English v.0.48:

Sunder \Sun"der\, v. i.
   To part; to separate. [R.] --Shak.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Sunder \Sun"der\, n. [See Sunder, v. t., and cf. Asunder.]
   A separation into parts; a division or severance.
   [1913 Webster]

   In sunder, into parts. "He breaketh the bow, and cutteth
      the spear in sunder." --Ps. xlvi. 9.
      [1913 Webster]

WordNet (r) 3.0 (2006):

sunder
    v 1: break apart or in two, using violence

Moby Thesaurus II by Grady Ward, 1.0:

70 Moby Thesaurus words for "sunder":
   amputate, atomize, ax, bisect, break to pieces, break up, butcher,
   carve, chop, cleave, cut, cut away, cut in two, cut off, demolish,
   dichotomize, disassemble, disintegrate, disjoin, disjoint,
   dismantle, dissect, dissever, disunite, divide, divorce, excise,
   fissure, fragment, gash, hack, halve, hew, incise, jigsaw, lance,
   make mincemeat of, pare, part, pick to pieces, prune,
   pull in pieces, pull to pieces, pulverize, reduce to rubble, rend,
   rive, saw, scissor, sever, shatter, slash, slice, slit, smash,
   snip, split, take apart, tear, tear apart, tear to pieces,
   tear to shreds, tear to tatters, total, unbuild, undo, unmake,
   whittle, wrack up, wreck