noun (n)

• the trait of acting stupidly or rashly(noun.attribute)

  Synonym:
  folly, unwiseness
  Antonym:
  wisdom, wiseness
  

  source: wordnet30
• the quality of being rash and foolish(noun.cognition)

  Example:
  Adjusting to an insane society is total foolishness.
  

  Synonym:
  craziness, folly, madness
  

  source: wordnet30
• a stupid mistake(noun.act)

  Synonym:
  betise, folly, imbecility, stupidity
  

  source: wordnet30
• The quality of being foolish.(noun)

  source: webster1913