noun (n)

• anger produced by some annoying irritation(noun.feeling)

  Synonym:
  annoyance, chafe
  

  source: wordnet30
• the psychological state of being irritated or annoyed(noun.state)

  Synonym:
  annoyance, botheration, irritation
  

  source: wordnet30
• something or someone that causes anxiety; a source of unhappiness(noun.cognition)

  Synonym:
  concern, headache, worry
  

  source: wordnet30
• the act of troubling or annoying someone(noun.act)

  Synonym:
  annoyance, annoying, irritation
  

  source: wordnet30
• The act of vexing, or the state of being vexed; agitation; disquiet; trouble; irritation.(noun)

  source: webster1913