noun (n)

• (psychiatry) a relatively permanent state of worry and nervousness occurring in a variety of mental disorders, usually accompanied by compulsive behavior or attacks of panic(noun.state)

  Synonym:
  anxiousness
  

  source: wordnet30
• a vague unpleasant emotion that is experienced in anticipation of some (usually ill-defined) misfortune(noun.feeling)

  source: wordnet30
• Concern or solicitude respecting some thing or event, future or uncertain, which disturbs the mind, and keeps it in a state of painful uneasiness.(noun)

  source: webster1913