noun (n)

• propriety in manners and conduct(noun.attribute)

  Synonym:
  decorousness
  Antonym:
  indecorousness, indecorum
  

  source: wordnet30
• Propriety of manner or conduct; grace arising from suitableness of speech and behavior to one's own character, or to the place and occasion; decency of conduct; seemliness; that which is seemly or suitable.(noun)

  source: webster1913