The Collaborative International Dictionary of English v.0.48:

Smile \Smile\ (sm[imac]l), v. i. [imp. & p. p. Smiled
   (sm[imac]ld); p. pr. & vb. n. Smiling.] [OE. smilen; akin
   to Dan. smile, Sw. smila, MHG. smielen, smieren, L. mirari to
   wonder at, Skr. smi to smile; and probably to E. smicker.
   [root]173. Cf. Admire, Marvel, Smirk.]
   1. To express amusement, pleasure, moderate joy, or love and
      kindness, by the features of the face; to laugh silently.
      [1913 Webster]

            He doth nothing but frown. . . . He hears merry
            tales and smiles not.                 --Shak.
      [1913 Webster]

            She smiled to see the doughty hero slain. --Pope.
      [1913 Webster]

            When last I saw thy young blue eyes, they smiled.
                                                  --Byron.
      [1913 Webster]

   2. To express slight contempt by a look implying sarcasm or
      pity; to sneer.
      [1913 Webster]

            'T was what I said to Craggs and Child,
            Who praised my modesty, and smiled.   --Pope.
      [1913 Webster]

   3. To look gay and joyous; to have an appearance suited to
      excite joy; as, smiling spring; smiling plenty.
      [1913 Webster]

            The desert smiled,
            And paradise was opened in the wild.  --Pope.
      [1913 Webster]

   4. To be propitious or favorable; to favor; to countenance;
      -- often with on; as, to smile on one's labors.
      [1913 Webster]

WordNet (r) 3.0 (2006):

smiling
    adj 1: smiling with happiness or optimism; "Come to my arms, my
           beamish boy!"- Lewis Carroll; "a room of smiling faces";
           "a round red twinkly Santa Claus" [syn: beamish,
           smiling(a), twinkly]
    n 1: a facial expression characterized by turning up the corners
         of the mouth; usually shows pleasure or amusement [syn:
         smile, smiling, grin, grinning]

Moby Thesaurus II by Grady Ward, 1.0:

67 Moby Thesaurus words for "smiling":
   beam, beaming, beatific, beatified, blessed, blissful, blithe,
   blithesome, bright, bright and sunny, bright smile, broad grin,
   capering, cheerful, cheery, chirping, dancing, ear-to-ear grin,
   elated, eupeptic, euphoric, exalted, exhilarated, flushed,
   flushed with joy, gay, genial, glad, gladsome, gleaming smile,
   glowing, glowing smile, grin, grinning, happy, high, hopeful,
   idiotic grin, in good spirits, in high spirits, irrepressible,
   joyful, joyous, laughing, leaping, of good cheer, optimistic,
   pleasant, purring, radiant, riant, rosy, sanguine, sanguineous,
   sardonic grin, simper, singing, smile, smirk, smirking, sparkling,
   starry-eyed, stupid grin, sunny, thrice happy, toothful grin,
   winsome