The Collaborative International Dictionary of English v.0.48:

Vast \Vast\ (v[.a]st), a. [Compar. Vaster (v[.a]st"[~e]r);
   superl. Vastest.] [L. vastus empty, waste, enormous,
   immense: cf. F. vaste. See Waste, and cf. Devastate.]
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   1. Waste; desert; desolate; lonely. [Obs.]
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            The empty, vast, and wandering air.   --Shak.
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   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.
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            Through the vast and boundless deep.  --Milton.
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   3. Very great in numbers, quantity, or amount; as, a vast
      army; a vast sum of money.
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   4. Very great in force; mighty; as, vast labor.
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   5. Very great in importance; as, a subject of vast concern.
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   Syn: Enormous; huge; immense; mighty.
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