The Collaborative International Dictionary of English v.0.48:

Grandeur \Gran"deur\, n. [F., fr. grand. See Grand.]
   The state or quality of being grand; vastness; greatness;
   splendor; magnificence; stateliness; sublimity; dignity;
   elevation of thought or expression; nobility of action.
   [1913 Webster]

         Nor doth this grandeur and majestic show
         Of luxury . . . allure mine eye.         --Milton.

   Syn: Sublimity; majesty; stateliness; augustness; loftiness.
        See Sublimity.
        [1913 Webster]

WordNet (r) 3.0 (2006):

grandeur
    n 1: the quality of being magnificent or splendid or grand; "for
         magnificence and personal service there is the Queen's
         hotel"; "his `Hamlet' lacks the brilliance that one
         expects"; "it is the university that gives the scene its
         stately splendor"; "an imaginative mix of old-fashioned
         grandeur and colorful art"; "advertisers capitalize on the
         grandness and elegance it brings to their products" [syn:
         magnificence, brilliance, splendor, splendour,
         grandeur, grandness]
    2: the quality of elevation of mind and exaltation of character
       or ideals or conduct [syn: nobility, nobleness,
       magnanimousness, grandeur]

Moby Thesaurus II by Grady Ward, 1.0:

102 Moby Thesaurus words for "grandeur":
   Babylonian splendor, ampleness, amplitude, augustness, bigness,
   broadness, bulk, capaciousness, comprehensiveness, consequence,
   conspicuousness, copiousness, courtliness, dignifiedness, dignity,
   distinction, elaborateness, elegance, elevation, eminence,
   enormity, enormousness, exaltation, excellence, expanse,
   expansiveness, extensiveness, formidableness, fullness,
   generousness, gigantism, glory, gorgeousness, grandiosity,
   grandness, gravity, great scope, greatness, high mightiness,
   hugeness, immensity, importance, imposingness, impressiveness,
   infinity, intensity, kingliness, largeness, lavishness, loftiness,
   lordliness, luxuriousness, luxury, magnificence, magnitude,
   majesty, mark, might, mightiness, muchness, nobility, nobleness,
   notability, note, outstandingness, plenitude, plushness, pomp,
   poshness, power, pride of bearing, pride of place, princeliness,
   prodigiousness, profundity, prominence, proud bearing, proudness,
   regality, resplendence, ritziness, sedateness, significance,
   sobriety, solemnity, spaciousness, splendidness, splendiferousness,
   splendor, state, stateliness, strength, stupendousness, sublimity,
   sumptuousness, supereminence, tallness, tremendousness, vastness,
   venerability, wideness, worthiness