Red flag
Meaning
A clear sign or indicator of a problem, danger, or something that should cause concern.
Origin
Imagine a battlefield in the 17th century, bristling with tension. A commander would raise a scarlet banner, not just to identify his troops, but to send a chilling signal: 'no quarter.' This wasn't merely a flag; it was a defiant declaration of war, signifying that no mercy would be given or expected once the fighting began. From these brutal military origins, where a red flag literally heralded imminent danger and conflict, the phrase transitioned into everyday language. It became a powerful shorthand for any clear sign or warning that trouble is brewing, a stark indicator that something is seriously amiss and demands immediate attention.
Examples
- His inability to make eye contact during the interview was a red flag for the hiring manager.
- The sudden, unexplained charges on my credit card immediately raised a red flag.