noun (n)

• the trait of being frivolous; not serious or sensible(noun.attribute)

  Synonym:
  frivolousness
  Antonym:
  earnestness, serious-mindedness, seriousness, sincerity
  

  source: wordnet30
• something of little value or significance(noun.artifact)

  Synonym:
  bagatelle, fluff, frippery
  

  source: wordnet30
• acting like a clown or buffoon(noun.act)

  Synonym:
  buffoonery, clowning, harlequinade, japery, prank
  

  source: wordnet30
• The condition or quality of being frivolous; also, acts or habits of trifling; unbecoming levity of disposition.(noun)

  source: webster1913