adjective, vast·er, vast·est.
- 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.
- unusually large in size, extent, degree, or number; immense
- (prenominal) (intensifier)in vast haste
- the vast mainly poetic immense or boundless space
- British dialect a very great amount or number
1570s, from Middle French vaste, from Latin vastus “immense, extensive, huge,” also “desolate, unoccupied, empty.” The two meanings probably originally attached to two separate words, one with a long -a- one with a short -a-, that merged in early Latin (see waste). Very popular early 18c. as an intensifier. Related: Vastly; vastness.