of very great area or extent; immense

the vast reaches of outer space.

of very great size or proportions; huge; enormous

vast piles of rubble left in the wake of the war.

very great in number, quantity, amount, etc.

vast sums of money.

very great in degree, intensity, etc.

an artisan of vast skill.

Literary . an immense or boundless expanse or space.

adjective

bounded , limited , little , narrow , small

adjective

all-inclusive , ample , astronomical , big , boundless , broad , capacious , colossal , comprehensive , detailed , endless , enormous , eternal , expanded , extensive , far-flung , far-reaching , forever , giant , gigantic , great , huge , illimitable , immeasurable , immense , infinite , limitless , mammoth , massive , measureless , monstrous , monumental , never-ending , prodigious , prolonged , spacious , spread-out , stretched-out , sweeping , titanic , tremendous , unbounded , unlimited , voluminous , widespread , behemoth , brobdingnagian , bunyanesque , cyclopean , elephantine , gargantuan , gigantesque , herculean , heroic , jumbo , massy , mastodonic , mighty , monster , mountainous , pythonic , stupendous , cosmic , grandiose , imponderable , large , untold , whopping , wide , worldwide