hit/knock somebody/something for six

hit (one) for six

To upset or overwhelm someone, especially suddenly or unexpectedly. Primarily heard in UK. News of my father's sudden death completely hit me for six.
See also: hit, six

hit/knock somebody/something for ˈsix

(British English)
1 (often of something unpleasant) surprise somebody a lot: It really hit me for six to find that my father had written about me in his book.
2 completely destroy a plan, an idea, a suggestion, etc.; knock somebody/something over/down: The stock market crash has hit the economy for six.Toby took a step backwards and knocked the vase for six.
In cricket, if you hit the ball a long distance you score six runs.