From Longman Dictionary of Contemporary Englishsmash hitˈsmash hit noun [countable] APSUCCESSFULa very successful new play, book, film etc They had a smash hit with their first single.
Examples from the Corpus
smash hit• It may not be the London Palladium but it is a smash hit!• Have a great day and we hope your dot.com venture is a smash hit.• Not since the surprise smash hit of the year cast a rosy glow over Shore's vehicle.• Daly has been, quite literally, the smash hit of the Masters with the crowds, attracting the biggest galleries. 