[1] : The Collaborative International Dictionary of English v.0.48

vastly \vast"ly\, adv.
   to a vast extent or degree; very greatly; immensely. --jer.
   taylor.
   1913 webster

[2] : WordNet (r) 2.0

vastly
     adv : 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" syn: immensely
see also:
immensely 

[3] : Moby Thesaurus II by Grady Ward, 1.0

27 moby thesaurus words for "vastly":
   abroad, almost entirely, broadly, colossally, considerably,
   enormously, exceedingly, extensively, extremely, far and near,
   far and wide, gigantically, greatly, hugely, immensely, infinitely,
   on all sides, on every side, prodigiously, right and left,
   stupendously, substantially, titanically, tremendously, very much,
   widely, worlds

Vastly >> V Words
Vastly, definition of term: Vastly
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