The Collaborative International Dictionary of English v.0.48:

Melodramatic \Mel`o*dra*mat"ic\, a. [Cf. F. m['e]lodramatique.]
   Of or pertaining to melodrama; like or suitable to a
   melodrama; unnatural in situation or action. --
   Mel`o*dra*mat"ic*al*ly, adv.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Dramatic \Dra*mat"ic\ (dr[.a]*m[a^]t"[i^]k), Dramatical
\Dra*mat"ic*al\ (dr[.a]*m[a^]t"[i^]*kal), a. [Gr. dramatiko`s,
   fr. dra^ma: cf. F. dramatique.]
   Of or pertaining to the drama; as, dramatic arts. [WordNet
   sense 3]
   [1913 Webster]

   2. suitable to or characteristic of or having the qualities
      of, a drama; theatrical; as, a dramatic entrance in a
      swirling cape; a dramatic rescue at sea. Opposite of
      undramatic. [WordNet sense 1] [Narrower terms:
      melodramatic; awe-inspiring, spectacular]
      [WordNet 1.5]

            The emperor . . . performed his part with much
            dramatic effect.                      --Motley.
      [1913 Webster]

   3. striking in appearance or effect; vivid; having a
      thrilling effect; as, a dramatic sunset; a dramatic pause.
      [WordNet sense 2]

   Syn: spectacular, striking.
        [WordNet 1.5]

   4. (Music) marked by power and expressiveness and a
      histrionic or theatrical style; -- of a singer or singing
      voice; as, a dramatic tenor; a dramatic soprano.
      Contrasted to lyric. [WordNet sense 4]
      [WordNet 1.5]

WordNet (r) 3.0 (2006):

melodramatic
    adj 1: having the excitement and emotional appeal of melodrama;
           "a melodramatic account of two perilous days at sea"
    2: characteristic of acting or a stage performance; often
       affected; "histrionic gestures"; "an attitude of melodramatic
       despair"; "a theatrical pose" [syn: histrionic,
       melodramatic]

Moby Thesaurus II by Grady Ward, 1.0:

55 Moby Thesaurus words for "melodramatic":
   Barnumesque, actor-proof, all-star, ballet, balletic, cinematic,
   cinematographic, cloak-and-dagger, dramatic, dramatical,
   dramaturgic, emotionalistic, emotive, exaggerated, film, filmic,
   ham, hammy, histrionic, hokey, hysteric, legitimate, lurid, milked,
   monodramatic, movie, nonrational, operatic, overacted, overdone,
   overdrawn, overemotional, overplayed, overworked, overwrought,
   scenic, schmaltzy, sensational, sensationalistic, spectacular,
   spine-chilling, stagelike, stageworthy, stagy, starstruck, stellar,
   theaterlike, theatrical, thespian, thrown away, underacted,
   underplayed, unreasoning, vaudevillian, yellow