VASTLY

vastly, immensely

(adverb) to an exceedingly great extent or degree; “He had vastly overestimated his resources”; “was immensely more important to the project as a scientist than as an administrator”

Source: WordNet® 3.1

Etymology

Adverb

vastly (comparative more vastly, superlative most vastly)

Greatly, in a vast manner.

Synonyms

• exceedingly, extremely, highly, immensely, supremely, tremendously

Source: Wiktionary

Vast"ly, adv.

Definition: To a vast extent or degree; very greatly; immensely. Jer. Taylor.

VAST

Vast, a. [Compar. Vaster; superl. Vastest.] Etym: [L. vastus empty, waste, enormous, immense: cf. F. vaste. See Waste, and cf. Devastate.]

1. Waste; desert; desolate; lonely. [Obs.] 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 importance; as, a subject of vast concern.

Syn.

– Enormous; huge; immense; mighty.

Vast, n.

Definition: A waste region; boundless space; immensity. "The watery vast." Pope. Michael bid sound The archangel trumpet. Through the vast of heaven It sounded. Milton.

Source: Webster’s Unabridged Dictionary 1913 Edition