Wiktionary
crackback
a. (context American football English) Describing a block in which the blocker, positioned wide, blocks back towards where the ball was snapped.
Usage examples of "crackback".
Not as The President: a broken little bully who would sacrifice us all to save himself -- if he still had the choice -- but the same kind of sympathy I might feel, momentarily, for a vicious cheap-shot linebacker whose long career comes to a sudden end one Sunday afternoon when some rookie flanker shatters both his knees with a savage crackback block.
For the first time in fifteen years, ever since he had been taken out of the National Football League by a crackback block, his left knee hurt.