Definitions of threat:

• noun:   declaration of an intention or a determination to inflict harm on another

  Example: "His threat to kill me was quite explicit"

• noun:   a warning that something unpleasant is imminent

  Example: "They were under threat of arrest"

• noun:   something that is a source of danger

  Example: "Earthquakes are a constant threat in Japan"

• noun:   a person who inspires fear or dread
• name:  A surname (very rare: popularity rank in the U.S.: #29538)