noun (n)

• a pressing or urgent situation(noun.state)

  Example:
  The health-care exigency.
  

  source: wordnet30
• a sudden unforeseen crisis (usually involving danger) that requires immediate action(noun.event)

  Synonym:
  emergency, pinch
  

  source: wordnet30
• The state of being exigent; urgent or exacting want; pressing necessity or distress; need; a case demanding immediate action, supply, or remedy; as, an unforeseen exigency.(noun)

  source: webster1913