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):

severed
    adj 1: detached by cutting; "cut flowers"; "a severed head"; "an
           old tale of Anne Bolyn walking the castle walls with her
           poor cut-off head under her arm" [syn: severed, cut
           off]

Moby Thesaurus II by Grady Ward, 1.0:

20 Moby Thesaurus words for "severed":
   cleft, cloven, cracked, cut, in pieces, in shreds, lacerate,
   lacerated, mangled, mutilated, quartered, ragged, rent, riven,
   shredded, slit, splintered, split, tattered, torn