Synonyms for Voluminous:

adj.

ample (adjective)
bountiful, broad, big, heavy, bounteous, wide, abounding, substantial, generous.
big (adjective)
tremendous, huge, colossal, enormous, gigantic, sizable, mammoth, prodigious, stuffed, immense, vast.
bulky (adjective)
long, high.
full (adjective)
overflowing.
generous (adjective)
plenitudinous.
great (adjective)
towering, humongous.
large (adjective)
big, roomy, grandiose, humongous, ample, awesome, gargantuan, gigantic, impressive, copious, grand, great, magnificent, spacious, bulky, immense, colossal, large, sizable, vast, massive, tremendous, lofty, extensive, baggy, enormous, soaring, comprehensive, giant, cavernous, huge, prodigious, capacious, princely, elephantine, majestic, towering, expansive, mammoth, generous.
size (adjective)
measurable, amplitudinous, corpulent, dimensional, wide, sizable, big, large, expansive, broad, magnificent, portly, extensive, long, great, bulky, chunky, high.
voluminous (adjective)
ample, abundant, capacious, expansive, covering, massive, cavernous, extensive, comprehensive, swelling, great, full, bulky, large, copious, spacious, roomy.

n.

boot-cut, button-down, backless, best, brief, Clingy, full, swelling, A-LINE, casual, button-through. written, newsy, circular, covering, enclosed, unanswered, returnable, textual, valid, on paper, in black and white. lidded, pressurized, graduated, tighten, leaky, tamper-proof, airtight, unattended, stuffed. plenitudinous, substantial, bounteous, give, bountiful, heavy. profuse (noun)
overflowing, luxuriant, abounding, bountiful.
voluminous (noun)
abundant, big, copious, extensive, large.

Other synonyms:

bounteous, leaky, unattended, plenitudinous, tamper-proof. lidded, bountiful, pressurized. graduated. substantial, stuffed. heavy. full. Other relevant words:
plenitudinous, bountiful, full, stuffed, covering, substantial, swelling, tamper-proof, bounteous, pressurized, unattended, heavy, lidded, abundant.

Usage examples for voluminous

  1. He promised to be a faithful and voluminous correspondent, and she knew she would live upon his letters. – His Sombre Rivals by E. P. Roe
  2. This startling color combination was enhanced by a red sash, which, though faded in streaks, was wide and tied at the back in a voluminous bow. – Marjorie's Vacation by Carolyn Wells
  3. It was in the Tower that the main bulk of his voluminous writings were produced. – Raleigh by Edmund Gosse