Vast (vȧst), a. [Compar.Vaster (?); superl.Vastest.] [L. vastus empty, waste, enormous, immense: cf. F. vaste. See Waste, and cf. Devastate.]
1. Waste; desert; desolate; lonely.
The empty, vast, and wandering air. Shak.
2. Of great extent; very spacious or large; also, huge in bulk; immense; enormous; as, the vast ocean; vast mountains; the vast empire of Russia.
Through the vast and boundless deep. Milton.
3. Very great in numbers, quantity, or amount; as, a vast army; a vast sum of money.
4. Very great in force; mighty; as, vast labor.
5. Very great in importance; as, a subject of vast concern.
Syn. — Enormous; huge; immense; mighty.