red flag
idiomPart offlag
red flag — idiom
1. a clear sign that something is wrong, dangerous, or likely to cause serious trou
1.idiom
Definition
a clear sign that something is wrong, dangerous, or likely to cause serious trouble.
Example
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.