[syn: improbable, marvelous, marvellous, tall(a)]
The Collaborative International Dictionary of English v.0.48:
marvellous \marvellous\ adj.
   Marvelous.
   Syn: improbable, marvelous, tall(prenominal).
        [WordNet 1.5]
The Collaborative International Dictionary of English v.0.48:
Marvelous \Mar"vel*ous\, a. [OE. merveillous, OF. merveillos, F.
   Merveilleux. See Marvel, n.] [Written also marvellous.]
   1. Exciting wonder or surprise; astonishing; wonderful.
      [1913 Webster]
            This is the Lord's doing; it is marvelous in our
            eyes.                                 --Ps. cxiii.
                                                  23.
      [1913 Webster]
   2. Partaking of the character of miracle, or supernatural
      power; incredible; so improbable as to defy belief.
      [1913 Webster +PJC]
            The marvelous fable includes whatever is
            supernatural, and especially the machines of the
            gods.                                 --Pope.
      [1913 Webster]
   The marvelous, that which exceeds natural power, or is
      preternatural; that which is wonderful; -- opposed to the
      probable.
      [1913 Webster]
   Syn: Wonderful; astonishing; surprising; strange; improbable;
        incredible.
   Usage: Marvelous, Wonderful. We speak of a thing as
          wonderful when it awakens our surprise and admiration;
          as marvelous when it is so much out of the ordinary
          course of things as to seem nearly or quite
          incredible.
          [1913 Webster]
WordNet (r) 3.0 (2006):
marvellous
    adj 1: extraordinarily good or great ; used especially as
           intensifiers; "a fantastic trip to the Orient"; "the film
           was fantastic!"; "a howling success"; "a marvelous
           collection of rare books"; "had a rattling conversation
           about politics"; "a tremendous achievement" [syn:
           fantastic, grand, howling(a), marvelous,
           marvellous, rattling(a), terrific, tremendous,
           wonderful, wondrous]
    2: being or having the character of a miracle [syn: marvelous,
       marvellous, miraculous]
    3: too improbable to admit of belief; "a tall story" [syn:
       improbable, marvelous, marvellous, tall(a)]
Moby Thesaurus II by Grady Ward, 1.0:
30 Moby Thesaurus words for "marvellous":
   amazing, astonishing, astounding, breathtaking, crazy, excellent,
   extraordinary, fabulous, fantastic, glorious, great, groovy,
   incredible, marvy, mind-boggling, miraculous, phenomenal,
   remarkable, sensational, smashing, spectacular, splendid, super,
   superb, surprising, terrific, unbelievable, unparalleled, wild,
   wonderful