Synonyms for Stupendous:

adj.

surprising (adjective)
astonishing.
wonderful, amazing (adjective)
great, phenomenal, fantastic, astonishing, enormous, prodigious, marvelous, wondrous, colossal, fabulous, gigantic, tremendous, monumental, miraculous, vast, astounding, monster, huge.

n.

high, king-size, great, wide. fantastical, fabulous, miraculous, unbelievable, incredible, wonderful, marvelous, fantastic, amazing, wondrous, phenomenal, astounding, good, astonishing. mammoth, vast, mountainous, whopping, walloping, jumbo, elephantine, Massy, titanic, mighty, massive, heroic, huge, gargantuan, mastodonic, gigantic, monster, behemoth, Pythonic, giant, monumental, enormous, Gigantesque, tremendous, Bunyanesque, herculean, monstrous, cyclopean, immense, Brobdingnagian. breathtaking (noun)
miraculous, marvelous, grand.
stupendous (noun)
colossal, large, big, prodigious.

Other synonyms:

walloping, Brobdingnagian, monstrous, Gigantesque, miraculous, Bunyanesque, Pythonic, Massy, astounding, cyclopean, mastodonic. astonishing, elephantine, tremendous, whopping, vast, amazing, marvelous, monumental, titanic, mountainous, gigantic, gargantuan, immense, enormous, wondrous, huge. heroic, herculean, fabulous, phenomenal, wonderful. massive, incredible, fantastical, mighty, unbelievable. monster, fantastic. exalted
grand.
Other relevant words:
huge, herculean, monumental, fabulous, tremendous, fantastical, fantastic, king-size, wondrous, jumbo, phenomenal, marvelous, elephantine, mighty, incredible, Pythonic, Massy, gargantuan, whopping, Bunyanesque, giant, wide, mastodonic, grand, monstrous, monster, astonishing, massive, gigantic, great, heroic, wonderful, miraculous, vast, behemoth, high, mountainous, amazing, titanic, walloping, Brobdingnagian, Gigantesque, good, unbelievable, immense, mammoth, enormous, cyclopean, astounding.

Usage examples for stupendous

  1. Sometimes she wondered what Madame Sennier's life had been while Jacques Sennier was composing Le Paradis Terrestre, how long he had taken in the creation of that stupendous success. – The Way of Ambition by Robert Hichens
  2. Along its western shores extends the flat limestone country, partly wooded and partly prairie land, running from that point for hundreds of miles up to the very foot of the Rocky Mountains, where the primitive rocks again make their appearance in the rugged peaks of that stupendous chain. – Popular Adventure Tales by Mayne Reid
  3. How else was it possible for Eternal Love to give so stupendous a charge and power in language so tender? – Church and State as Seen in the Formation of Christendom by T. W. Allies