The Collaborative International Dictionary of English v.0.48:

Superb \Su*perb"\, a. [F. superbe, L. superbus, fr. super over.
   See Super-.]
   1. Grand; magnificent; august; stately; as, a superb edifice;
      a superb colonnade.
      [1913 Webster]

   2. Rich; elegant; as, superb furniture or decorations.
      [1913 Webster]

   3. Showy; excellent; grand; as, a superb exhibition.
      [1913 Webster]

   Superb paradise bird (Zool.), a bird of paradise
      (Paradisaea superba syn. Lophorina superba) having the
      scapulars erectile, and forming a large ornamental tuft on
      each shoulder, and a large gorget of brilliant feathers on
      the breast . The color is deep violet, or nearly black,
      with brilliant green reflections. The gorget is bright
      metallic green.

   Superb warber. (Zool.) See Blue wren, under Wren.
      [1913 Webster] -- Su*perb"ly, adv. -- Su*perb"ness, n.
      [1913 Webster]

WordNet (r) 3.0 (2006):

superb
    adj 1: of surpassing excellence; "a brilliant performance"; "a
           superb actor" [syn: brilliant, superb]
    2: surpassingly good; "a superb meal"

Moby Thesaurus II by Grady Ward, 1.0:

115 Moby Thesaurus words for "superb":
   Babylonian, Corinthian, admirable, august, awe-inspiring, awful,
   bad, barbaric, best, boss, breathtaking, brilliant, classic, cool,
   crashing, dazzling, deluxe, distinguished, divine, elaborate,
   elegant, elevated, eminent, exalted, excellent, exceptional,
   exquisite, extraordinary, extravagant, fabulous, famous, fancy,
   fantastic, fine, first-rate, gilt-edged, glorious, godlike, golden,
   gorgeous, grand, grandiose, great, heavenly, heroic, high, hot,
   immense, imposing, impressive, incredible, lauded, lofty,
   luxurious, magic, magnanimous, magnificent, majestic, marvelous,
   matchless, mind-blowing, mind-boggling, miraculous, noble,
   noteworthy, optimal, optimum, opulent, out of sight, outstanding,
   palatial, peerless, perfect, plush, posh, prime, princely,
   prominent, proud, renowned, resplendent, ritzy, rousing,
   sensational, smashing, soaring, solid, splendacious, splendid,
   splendiferous, splendorous, staggering, stately, sterling,
   striking, stupendous, sublime, sumptuous, super, supereminent,
   superexcellent, superfancy, superfine, superior, superlative,
   swank, swanky, swell, terrific, towering, tremendous, unbelievable,
   unreal, very best, wonderful