/ ˈblɒkbʌstə(r); NAmE ˈblɑːk-/ noun
( informal ) something very successful, especially a very successful book or film / movie :
a Hollywood blockbuster
► block·bust·ing adjective :
a blockbusting performance
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WORD ORIGIN
1940s (denoting a huge aerial bomb capable of destroying a whole block of streets): from block + buster .