Be caught on the wrong foot phrase informal
If you are caught on the wrong foot, you are unprepared for something that happens quickly and unexpectedly.
We were caught on the wrong foot by his financial scandal.
I was caught on the wrong foot when the boss asked the reason why I was absent from work yesterday.
To greatly surprise, shock, or confuse someone
An exclamation of shock or surprise
The phrase "be caught on the wrong foot " is also used in the active form "catch somebody on the wrong foot". Both convey the same meaning.
His question caught me on the wrong foot.
If someone has a cast iron stomach, they have a strong stomach that can digest unusual food and even bad food without being ill.
Jimmy must have a cast-iron stomach, when he drank milk with lime juice and felt perfectly fine afterward.