Adverb: vastly vãst-lee
- To an exceedingly great extent or degree
"He had vastly overestimated his resources";
- immensely, colossally, gigantically, enormously, tremendously, hugely, staggeringly
- To a great extent; over a large range or scale
"salaries vary vastly";
- enormously, exceedingly, extremely, terrifically [informal], tremendously, hugely, immensely, massively [informal], greatly