The Collaborative International Dictionary of English v.0.48:

Engross \En*gross"\, v. t. [imp. & p. p. Engrossed; p. pr. &
   vb. n. Engrossing.] [F., fr. pref. en- (L. in) + gros
   gross, grosse, n., an engrossed document: cf. OF. engrossir,
   engroissier, to make thick, large, or gross. See Gross.]
   1. To make gross, thick, or large; to thicken; to increase in
      bulk or quantity. [Obs.]
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            Waves . . . engrossed with mud.       --Spenser.
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            Not sleeping, to engross his idle body. --Shak.
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   2. To amass. [Obs.]
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            To engross up glorious deeds on my behalf. --Shak.
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   3. To copy or write in a large hand (en gross, i. e., in
      large); to write a fair copy of in distinct and legible
      characters; as, to engross a deed or like instrument on
      parchment.
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            Some period long past, when clerks engrossed their
            stiff and formal chirography on more substantial
            materials.                            --Hawthorne.
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            Laws that may be engrossed on a finger nail. --De
                                                  Quincey.
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   4. To seize in the gross; to take the whole of; to occupy the
      attention completely; to absorb; as, the subject engrossed
      all his thoughts.
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   5. To purchase either the whole or large quantities of, for
      the purpose of enhancing the price and making a profit;
      hence, to take or assume in undue quantity, proportion, or
      degree; as, to engross commodities in market; to engross
      power.
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   Engrossed bill (Legislation), one which has been plainly
      engrossed on parchment, with all its amendments,
      preparatory to final action on its passage.

   Engrossing hand (Penmanship), a fair, round style of
      writing suitable for engrossing legal documents,
      legislative bills, etc.

   Syn: To absorb; swallow up; imbibe; consume; exhaust; occupy;
        forestall; monopolize. See Absorb.
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WordNet (r) 3.0 (2006):

engrossed
    adj 1: giving or marked by complete attention to; "that
           engrossed look or rapt delight"; "then wrapped in
           dreams"; "so intent on this fantastic...narrative that
           she hardly stirred"- Walter de la Mare; "rapt with
           wonder"; "wrapped in thought" [syn: captive,
           absorbed, engrossed, enwrapped, intent,
           wrapped]
    2: written formally in a large clear script, as a deed or other
       legal document

Moby Thesaurus II by Grady Ward, 1.0:

112 Moby Thesaurus words for "engrossed":
   absent, absentminded, absorbed, absorbed in, abstracted, assiduous,
   autograph, autographic, bemused, buried in, buried in thought,
   busy, calligraphic, castle-building, caught up in, chirographic,
   consumed, contemplating, contemplative, cursive, daydreaming,
   daydreamy, deep, devoted, devoted to, diligent, dreaming, dreamy,
   drowsing, ecstatic, elsewhere, engaged, engaged in thought,
   engrossed in, engrossed in thought, faraway, flowing, graphic,
   graphoanalytic, graphologic, graphometric, half-awake, holograph,
   holographic, immersed, immersed in, immersed in thought,
   in a reverie, in longhand, in shorthand, in the clouds, in writing,
   industrious, inscribed, intent, intent on, introspective, involved,
   italic, italicized, longhand, lost, lost in, lost in thought,
   manuscript, meditating, meditative, monomaniacal, monopolized,
   mooning, moonraking, museful, musing, napping, nodding, oblivious,
   obsessed, occupied, on paper, penciled, penned, pensive,
   pipe-dreaming, preoccupied, printed, rapt, running, scriptorial,
   scriptural, sedulous, shorthand, single-minded, somewhere else,
   stargazing, studious, studying, stylographic, submerged,
   submerged in, swept up, taken up, taken up with, totally absorbed,
   transported, unconscious, woolgathering, wrapped, wrapped in,
   wrapped in thought, wrapped up, wrapped up in, written