The Collaborative International Dictionary of English v.0.48:

Scrag \Scrag\ (skr[a^]g), n. [Cf. dial. Sw. skraka a great dry
   tree, a long, lean man, Gael. sgreagach dry, shriveled,
   rocky. See Shrink, and cf. Scrog, Shrag, n.]
   1. Something thin, lean, or rough; a bony piece; especially,
      a bony neckpiece of meat; hence, humorously or in
      contempt, the neck.
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            Lady MacScrew, who . . . serves up a scrag of mutton
            on silver.                            --Thackeray.
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   2. A rawboned person. [Low] --Halliwell.
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   3. A ragged, stunted tree or branch.
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   Scrag whale (Zool.), a North Atlantic whalebone whale
      (Agaphelus gibbosus). By some it is considered the young
      of the right whale.
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