extremely large in area, size, amount, etc. synonym huge a vast area of forest a vast crowd a vast amount of information At dusk bats appear in vast numbers. His business empire was vast. In the vast majority of cases, this should not be a problem. Your help made a vast difference. Renting the hall was a vast expense.
NAmE//væstnəs//
noun [uncountable, countable] the vastness of spaceSee vast in the Oxford Advanced Learner's DictionaryCheck pronunciation: vast