crackback
noun
crack·back ˈkrak-ˌbak 
: a blind-side block on a defensive back in football by a pass receiver who starts downfield and then cuts back to the middle of the line
Example Sentences
Recent Examples on the Web Burfict loses money due to Steelers’ hit Pittsburgh Steelers’ wide receiver JuJu Smith-Schuster may have been suspended a game for his crackback block on Vontaze Burfict on Dec. 4, but the Bengals linebacker has really been hurt by it. 
Jim Owczarski, Cincinnati.com, 17 Dec. 2017
Jim Owczarski, Cincinnati.com, 17 Dec. 2017 Word History
First Known Use
1967, in the meaning defined above