noun (n)

• the property of being comparatively great in weight(noun.attribute)

  Example:
  The heaviness of lead.
  

  Synonym:
  weightiness
  Antonym:
  lightness, weightlessness
  

  source: wordnet30
• persisting sadness(noun.feeling)

  Example:
  Nothing lifted the heaviness of her heart after her loss.
  

  source: wordnet30
• an oppressive quality that is laborious and solemn and lacks grace or fluency(noun.attribute)

  Example:
  His lectures tend to heaviness and repetition.
  

  Synonym:
  ponderousness
  

  source: wordnet30
• used of a line or mark(noun.attribute)

  Synonym:
  thickness
  

  source: wordnet30
• unwelcome burdensome difficulty(noun.attribute)

  Synonym:
  burdensomeness, onerousness, oppressiveness
  

  source: wordnet30
• The state or quality of being heavy in its various senses; weight; sadness; sluggishness; oppression; thickness.(noun)

  source: webster1913