noun (n)

• the feeling caused by disagreeable stimuli; one pole of a continuum of states of feeling(noun.feeling)

  Antonym:
  pleasantness
  

  source: wordnet30
• the quality of giving displeasure(noun.attribute)

  Example:
  The recent unpleasantness of the weather.
  

  Antonym:
  pleasantness, sweetness
  

  source: wordnet30