To a very great extent; immensely.
 business practices differ vastly from country to country
as submodifier a bunch of talented and vastly experienced players
 Example sentencesExamples
-  The show included three sculptures replicating unmarked packets of sweetener at vastly larger-than-life size.
 -  Twelve years later, the situation had vastly improved.
 -  This instance illustrates the social construction of acceptability, whereby different audiences may respond to the same set of works in vastly different ways.
 -  The 1993 American remake is vastly inferior.
 -  Technology vastly increases children's capacity for secrecy and their vulnerability to exploitation.