The Collaborative International Dictionary of English v.0.48:

chew \chew\ (ch[udd]), v. t. [imp. & p. p. Chewed (ch[udd]d);
   p. pr. & vb. n. Chewing.] [As ce['o]wan, akin to D. kauwen,
   G. kauen. Cf. Chaw, Jaw.]
   1. To bite and grind with the teeth; to masticate.
      [1913 Webster]

   2. To ruminate mentally; to meditate on.
      [1913 Webster]

            He chews revenge, abjuring his offense. --Prior.
      [1913 Webster]

   To chew the cud, to chew the food over again, as a cow; to
      ruminate; hence, to meditate.
      [1913 Webster]

            Every beast the parteth the hoof, and cleaveth the
            cleft into two claws, and cheweth the cud among the
            beasts, that ye shall eat.            --Deut. xxiv.
                                                  6.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

chewing \chewing\ n.
   biting your food in your mouth so it becomes soft enough to
   swallow.

   Syn: chew, mastication.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

chewing
    n 1: biting and grinding food in your mouth so it becomes soft
         enough to swallow [syn: chew, chewing, mastication,
         manduction]

Moby Thesaurus II by Grady Ward, 1.0:

83 Moby Thesaurus words for "chewing":
   appetite, ass-reaming, bawling-out, cannibalism, carnivorism,
   carnivority, carnivorousness, chain-smoke, consumption, cropping,
   cud-chewing, cussing-out, deglutition, devouring, devourment,
   dieting, dining, drag, dressing, dressing-down, eating, epulation,
   feasting, feeding, gluttony, gobbling, going-over, grazing,
   habitual smoking, herbivorism, herbivority, herbivorousness,
   hunger, ingestion, jacking-up, licking, manducation, manducatory,
   mastication, masticatory, messing, munching, nibbling,
   nicotine addiction, nicotinic, nicotinism, nutrition, omnivorism,
   omnivorousness, omophagy, pantophagy, pasture, pasturing, pecking,
   puff, raking-down, reaming, reaming-out, regalement, relishing,
   roasting, ruminant, ruminating, rumination, savoring, setdown,
   smoke, smoking, smoking habit, snuffy, speaking-to, tabacism,
   tabacosis, tabagism, talking-to, tasting, tobacco, tobaccoism,
   tobaccolike, tobaccoy, vegetarianism, what-for, wolfing