cross mark (U+274C)

The emoji "❌" is a red circle with a diagonal line through it, also known as the "prohibited" or "not allowed" symbol. It is used in digital communication to indicate that something is not permitted, forbidden, or not acceptable. This emoji can be used in a variety of contexts, such as to decline a request, to indicate that a certain behavior is not allowed, or to express disapproval. It is a clear and concise way to communicate a negative message without using words. However, it's important to use it with caution as it can come off as harsh or dismissive.