If you hear someone say that something “threw me for a loop” it means that something surprised them to the point that they didn’t know what to do.
In general, the idiom to throw someone/something for a loop means to cause great surprise, confusion, or astonishment. The related idiom to knock someone/something for a loop has the same meaning.
The main idea is that things are going well, circumstances are good, and suddenly something unexpected happens that causes trouble, confusion, surprise, or amazement.
Example sentences using to throw someone for a loop.
1. Just when you think you have life figured out, something will come along and throw you for a loop. (Meaning, surprise you with some challenge or difficulty)
2. Here is one last grammar point that throws learners for a loop. (Meaning, causes learners to be confused)
3. The Brexit vote result threw Wall Street and the global markets for a loop. (Meaning, caused confusion and/or surprise)
4 Polar bears are getting thrown for a loop as the polar ice disappears due to global warming. (Meaning, the lack of habitat is causing confusion and trouble for the bears)
As the examples above illustrate, to throw someone/something for a loop is also used in passive constructions with the verbs to get and to be
to get thrown for a loop
to be thrown for a loop
Let’s look at the polar bear and Brexit examples using these passive constructions:
1. Polar bears are getting thrown for a loop by climate change.
2. Polar bears are being thrown for a loop by climate change.
1. Wall Street and the global markets got thrown for a loop by the Brexit vote.
2. Wall Street and the global markets were thrown for a loop by the Brexit vote.
Subject verb agreement is important in these constructions. Remember that it is the first verb (the finite verb) that needs to be changed so that it agrees with the subject.