knock (one) on (one's) ass(redirected from knock on ass)
knock (one) on (one's) ass
1. To cause one to become overwhelmed with emotion, bewilderment, or astonishment. The whole movie was very good, but that ending straight up knocked me on my ass! My dad is usually a very reserved guy, so to see him break down in tears like that really knocked me on my ass.
2. To cause one a great deal of debilitating hardship or heartache. Losing her job really knocked Sarah on her ass. I just hope she can pull herself together soon. If this next product flops, it's going to really knock us on our asses.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.