Synonyms for Cavernous:

adj.

all (adjective)
erectile.
hollow and large (adjective)
gaping, yawning, vast, huge, roomy, sunken, deep, spacious, concave, wide, broad.
large (adjective)
extensive, immense, generous, grandiose, voluminous, huge, broad, soaring, lofty, massive, copious, gargantuan, magnificent, comprehensive, impressive, mammoth, bulky, large, enormous, deep, giant, spacious, vast, expansive, big, towering, humongous, prodigious, princely, sizable, colossal, elephantine, baggy, roomy, ample, majestic, wide, capacious, awesome, great, tremendous, grand, gigantic.
unfathomable (adjective)
abyssal.

n.

beachfront, baronial, carpeted, burned-out, appointed, colonial, carbuncle, comfortable, brownstone. convex, concave, sunken, indented. abyssal, gaping, abysmal, yawning, wide. cavernous (noun)
expansive, hollow, erectile.
hollow (noun)
concave, sunken.

Other synonyms:

baronial, appointed, carpeted, burned-out, yawning, abyssal, beachfront, gaping. carbuncle, brownstone, indented, concave. colonial. abysmal, comfortable. Other relevant words:
brownstone, yawning, hollow, broad, carpeted, deep, comfortable, sunken, burned-out, concave, colonial, erectile, baronial, beachfront, convex, abysmal, gaping, carbuncle, indented, abyssal, wide, appointed.

Usage examples for cavernous

  1. Galen Albret himself made no sign, but sat, his head sunk forward, watching the men's faces from his cavernous eyes. – The Silent Places by Steward Edward White
  2. In order that the reader at his distance may figure this, he must imagine an indefinite cavernous expanse, with a low roof supported in vaulted arches by some thousand marble pillars, each with a different capital. – Familiar Spanish Travels by W. D. Howells
  3. His iron- gray hair, deeply carved features, and cavernous black eyes gave him the air of power that his reputation demanded. – Lady Rose's Daughter by Mrs. Humphry Ward