red flag

idiomPart offlag

red flag — idiom

1. a clear sign that something is wrong, dangerous, or likely to cause serious trou

1.慣用語
釋義

a clear sign that something is wrong, dangerous, or likely to cause serious trouble.

例句

When the builder asked for full payment in cash upfront, that was a red flag for the family.

A sudden change in a child's eating habits can be a red flag for teachers and parents.