The Collaborative International Dictionary of English v.0.48:

Sever \Sev"er\, v. i.
   1. To suffer disjunction; to be parted, or rent asunder; to
      be separated; to part; to separate. --Shak.
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   2. To make a separation or distinction; to distinguish.
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            The Lord shall sever between the cattle of Israel
            and the cattle of Egypt.              --Ex. ix. 4.
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            They claimed the right of severing in their
            challenge.                            --Macaulay.
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The Collaborative International Dictionary of English v.0.48:

Sever \Sev"er\, v. t. [imp. & p. p. Severed; p. pr. & vb. n.
   Severing.] [OF. sevrer, severer, to separate, F. sevrer to
   wean, fr. L. separare. See Separate, and cf. Several.]
   1. To separate, as one from another; to cut off from
      something; to divide; to part in any way, especially by
      violence, as by cutting, rending, etc.; as, to sever the
      head from the body.
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            The angels shall come forth, and sever the wicked
            from among the just.                  --Matt. xiii.
                                                  49.
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   2. To cut or break open or apart; to divide into parts; to
      cut through; to disjoin; as, to sever the arm or leg.
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            Our state can not be severed; we are one. --Milton.
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   3. To keep distinct or apart; to except; to exempt.
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            I will sever in that day the land of Goshen, in
            which my people dwell, that no swarms of flies shall
            be there.                             --Ex. viii.
                                                  22.
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   4. (Law) To disunite; to disconnect; to terminate; as, to
      sever an estate in joint tenancy. --Blackstone.
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WordNet (r) 3.0 (2006):

sever
    v 1: set or keep apart; "sever a relationship" [syn: sever,
         break up]
    2: cut off from a whole; "His head was severed from his body";
       "The soul discerped from the body" [syn: discerp, sever,
       lop]

Moby Thesaurus II by Grady Ward, 1.0:

108 Moby Thesaurus words for "sever":
   abandon, amputate, analyze, anatomize, atomize, ax, bisect, bob,
   break off, break up, butcher, carve, cease, change, chop,
   chop logic, cleave, contradistinguish, cut, cut away, cut in two,
   cut off, demarcate, demark, desynonymize, detach, dichotomize,
   difference, differentiate, discern, disconnect, discontinue,
   discriminate, disequalize, disjoin, disjoint, dissect, dissever,
   dissolve, distinguish, disunite, diversify, divide, divorce, dock,
   draw the line, end, excise, extricate, fissure, gash, hack, halve,
   hew, incise, individualize, individuate, jigsaw, lance,
   make a distinction, mark, mark off, mark out, mark the interface,
   modify, pare, part, particularize, personalize, pick out, prune,
   refine a distinction, rend, rive, saw, scissor, screen, screen out,
   segregate, select, separate, set a limit, set apart, set off,
   severalize, sieve, sieve out, sift, sift out, slash, slice, slit,
   snip, sort, sort out, specialize, split, split hairs, stop,
   subdivide, subtilize, sunder, suspend, tear, terminate, vary,
   whittle, winnow