The Collaborative International Dictionary of English v.0.48:

Chaw \Chaw\, n. [See Chaw, v. t.]
   1. As much as is put in the mouth at once; a chew; a quid.
      [Law]
      [1913 Webster]

   2. [Cf. Jaw.] The jaw. [Obs.] --Spenser.
      [1913 Webster]

   Chaw bacon, a rustic; a bumpkin; a lout. (Law)

   Chaw tooth, a grinder. (Law)
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Chaw \Chaw\, v. t. [imp. & p. p. Chawed; p. pr. & vb. n.
   Chawing.] [See Chew.]
   1. To grind with the teeth; to masticate, as food in eating;
      to chew, as the cud; to champ, as the bit.
      [1913 Webster]

            The trampling steed, with gold and purple trapped,
            Chawing the foamy bit, there fiercely stood.
                                                  --Surrey.
      [1913 Webster]

   2. To ruminate in thought; to consider; to keep the mind
      working upon; to brood over. --Dryden.
      [1913 Webster]

   Note: A word formerly in good use, but now regarded as
         vulgar.
         [1913 Webster]

WordNet (r) 3.0 (2006):

chaw
    n 1: a wad of something chewable as tobacco [syn: chew,
         chaw, cud, quid, plug, wad]
    v 1: chew without swallowing; "chaw tobacco"