1. Risk: (1) Indication of an approaching or imminent menace. (2) Negative event that can cause a risk to become a loss, expressed as an aggregate of risk, consequences of risk, and the likelihood of the occurrence of the event. A threat may be a natural phenomenon such as an earthquake, flood, storm, or a man made incident such as fire, power failure, sabotage, etc.
2. Computer security: Action or potential occurrence (whether or not malicious) to breach the security of the system by exploiting its known or unknown vulnerabilities. It may be caused by (1) gaining unauthorized access to stored information, (2) denial of service to the authorized users, or (3) introduction of false information to mislead the users or to cause incorrect system behavior (called spoofing). See also attack.
3. Law: Communicated intent to inflict harm or damage to a person or property to force someone's compliance or to restrict his or her freedom. Threatening behavior (including use of abusive or insulting words) is a generally a criminal offense punishable with imprisonment and/or a fine. A police officer may arrest anyone without warrant who is reasonably suspected of issuing an oral or written threat. See also assault.