knock/throw somebody for a loop
knock someone for a loop
1. Fig. to strike someone hard. You really knocked me for a loop. I hope that was an accident. DI was really knocked for a loop by the falling branch.
2. and throw someone for a loop Fig. to confuse or shock someone. (This is more severe and upsetting than throw someone a curve.) When Bill heard the news, it threw him for a loop. The manager knocked Bob for a loop by firing him on the spot.
knock for a loop
Also, throw for a loop; knock down or over with a feather ; knock sideways. Overcome with surprise or astonishment, as in The news of his death knocked me for a loop, or Being fired without any warning threw me for a loop, or Jane was knocked sideways when she found out she won. The first two of these hyperbolic colloquial usages, dating from the first half of the 1900s, allude to the comic-strip image of a person pushed hard enough to roll over in the shape of a loop. The third hyperbolic term, often put as You could have knocked me down with a feather, intimating that something so light as a feather could knock one down, dates from the early 1800s; the fourth was first recorded in 1925.