The word "⚫す" may contain a threatening meaning depending on the context, but the word itself does not have a clear meaning. Therefore, it is not possible to determine whether it is a threat or not based on the word alone. However, if the person is using the word "⚫す" to make demands or conditions that force you to do something, it can be considered as a threat.

Threats on the internet are a serious problem, just like real-life threats. If you feel threatened, consider reporting it to the police or your internet service provider immediately. It is also important to save the content of the threat.