Vast – English Flashcard for Vast for IELTS Updated: January 30, 2021 by Dr. Mohammad Hossein Hariri AslVast Vast (adj) /vɑːst/ US /væst/very great in amount, size, number, degree, etc. – gigantic, immense, extremely big – enormous, massive, huge, prodigiousIn this season, the birds start to migrate in vast numbers.Antonym: smallNoun: vastness