A "red flag" is a warning sign that indicates potential problems or dangers in a situation. It can refer to behaviors, patterns, or conditions that suggest something may not be right. For example, in relationships, a red flag might be controlling behavior or lack of communication, signaling that the relationship could be unhealthy. In various contexts, such as business, health, or sports, red flags serve as alerts to take caution. In business, a sudden drop in sales might be a red flag for financial issues. Recognizing these signs early can help individuals make informed decisions and avoid negative outcomes.