noun (n)

• incomprehensibility resulting from obscurity of meaning(noun.attribute)

  Synonym:
  opacity
  

  source: wordnet30
• the quality of being opaque to a degree; the degree to which something reduces the passage of light(noun.attribute)

  Antonym:
  clarity, clearness, uncloudedness
  

  source: wordnet30
• The state or quality of being impervious to light; opacity.(noun)

  source: webster1913