Verb threaten has 3 senses
  1. endanger, jeopardize, jeopardise, menace, threaten, imperil, peril - pose a threat to; present a danger to; "The pollution is endangering the crops"
    --1 is one way to exist, be
    Sample sentences:
    Something ----s somebody
    Something ----s something
    => Somebody ----s to INFINITIVE
  2. threaten - to utter intentions of injury or punishment against:"He threatened me when I tried to call the police"
    --2 is one way to
    Sample sentence:
    Sam cannot threaten Sue
  3. threaten - to be a menacing indication of something:"The clouds threaten rain"; "Danger threatens"
    --3 is one way to
    bode, portend, auspicate, prognosticate, omen, presage, betoken, foreshadow, augur, foretell, prefigure, forecast, predict
    Sample sentences:
    Something ----s
    Something ----s something