Word Study
vastly
CIDE DICTIONARY
vastly, adv.
To a vast extent or degree; very greatly; immensely. Jer. Taylor. [1913 Webster]
THESAURUS
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, worldsFor further exploring for "vastly" in Webster Dictionary Online