noun

• (informal) Something, such as a film or book, that sustains exceptional and widespread popularity and achieves enormous sales, as opposed to a box office bomb.
  "He was watching the blockbuster film series Harry Potter."
• (informal) Something, especially an event or a film, book or other creative work, that is intended to achieve high sales (perhaps indicated by large budgets or high advertising spending) or that is conceived on a large or epic scale
  ""General William Booth Enters into Heaven" is lusty, a blockbuster conception."
• (slang) Anything very large or powerful; a whopper.
  "“How nice," she responded to his invitation, “but I've got a blockbuster of a headache. I'm paying for last night. Call me tomorrow, will you?""
• (US) One who engages in blockbusting (technique encouraging people to sell property).
  "Whereas White residents fell prey to blockbusters who stoked fears of invading Negroes and plummeting housing values during the 1950s, African Americans confronted more-than-imagined difficulties in neighborhoods after the 1968 riots."