Source : Webster's Revised Unabridged Dictionary (1913)

Sympathize \Sym"pa*thize\, v. i. [imp. & p. p. {Sympathized}; p.
   pr. & vb. n. {Sympathizing}.] [F. sympathiser. See
   {Sympathy}.]
   1. To have a common feeling, as of bodily pleasure or pain.

            The mind will sympathize so much with the anguish
            and debility of the body, that it will be too
            distracted to fix itself in meditation.
                                                  --Buckminster.

   2. To feel in consequence of what another feels; to be
      affected by feelings similar to those of another, in
      consequence of knowing the person to be thus affected.

            Their countrymen . . . sympathized with their heroes
            in all their adventures.              --Addison.

   3. To agree; to be in accord; to harmonize. --Dryden.

Sympathize \Sym"pa*thize\, v. t.
   1. To experience together. [Obs.] ``This sympathized . . .
      error.'' --Shak.

   2. To ansew to; to correspond to. [Obs.] --Shak.

Source : WordNet®

sympathize
     v 1: share the feelings of; understand the sentiments of [syn: {sympathise}]
     2: be understanding of; "You don't need to explain--I
        understand!" [syn: {sympathise}, {empathize}, {empathise},
         {understand}]
     3: to feel or express sympathy or compassion [syn: {commiserate},
         {sympathise}]