verb (v)

• pose a threat to; present a danger to(verb.stative)

  Synonym:
  endanger, imperil, jeopardise, jeopardize, menace, peril
  

  source: wordnet30
• to utter intentions of injury or punishment against:(verb.communication)

  Example:
  He threatened me when I tried to call the police.
  

  source: wordnet30
• to be a menacing indication of something:(verb.communication)

  Example:
  The clouds threaten rain.
  Danger threatens.
  

  source: wordnet30
• To utter threats against; to menace; to inspire with apprehension; to alarm, or attempt to alarm, as with the promise of something evil or disagreeable; to warn.(verb)

  source: webster1913
• To use threats, or menaces; also, to have a threatening appearance.(verb)

  source: webster1913