Synonyms for Gigantic:

adj.

Herculean (adjective)
impressive, mighty, heroic.
all (adjective)
mammoth.
astronomical (adjective)
monumental.
big (adjective)
capacious, copious, roomy, extensive, bulky, sizable, ample, spacious, walloping, voluminous.
colossal (adjective)
mountainous, titanic.
elephantine (adjective)
grand, great, big, large, towering, humongous.
gigantic (adjective)
Brobdingnagian, cyclopean, prodigious, jumbo, monster, massive, mammoth, immense, colossal, elephantine, vast, stupendous, giant, monstrous, enormous, tremendous, huge, whopping, herculean, gargantuan.
great (adjective)
high.
large (adjective)
enormous, humongous, copious, cavernous, extensive, impressive, baggy, generous, elephantine, expansive, magnificent, immense, grandiose, grand, tremendous, bulky, massive, soaring, great, big, lofty, roomy, comprehensive, majestic, giant, spacious, vast, awesome, ample, voluminous, towering, gargantuan, sizable, princely, huge, mammoth, prodigious, colossal, capacious, large.

n.

high, study at enormous. mastodonic, cyclopean, Brobdingnagian, mountainous, walloping, titanic, stupendous, monumental, behemoth, herculean, Pythonic, Gigantesque, mighty, whopping, heroic, Massy, monstrous, Bunyanesque, monster, jumbo. gigantic (noun)
vast, huge, jumbo, giant, massive, titanic, colossal, gargantuan, whopping, Brobdingnagian, mammoth, monumental, immense, enormous.

Other synonyms:

mastodonic, Gigantesque, Massy, walloping, Pythonic, Bunyanesque, jumbo, cyclopean, Brobdingnagian. mountainous, titanic, monumental, whopping. heroic, monstrous, herculean, stupendous. monster. imposing
mighty.
tall
high.
Other relevant words:
high, stupendous, mighty, mountainous, monstrous, Brobdingnagian, mastodonic, Pythonic, monster, monumental, herculean, Massy, Gigantesque, Bunyanesque, titanic, jumbo, whopping, walloping, behemoth, heroic, cyclopean.

Usage examples for gigantic

  1. Then Jarl Eric addressed Gabrielle with so noble a grace, that with a smile of wonder she gazed on the gigantic grey hero, and gave him her beautiful hand to kiss. – Sintram and His Companions by Friedrich de la Motte Fouque Commentator: Charlotte M. Yonge
  2. Least of all did she discover anything gigantic in the kind- hearted Seraphin. – The Progressionists, and Angela. by Conrad von Bolanden