WordWeb Online

1. The trait of being frivolous; not serious or sensible
   - frivolousness
    
2. Something of little value or significance
   - bagatelle, fluff, frippery
    
3. Acting like a clown or buffoon
   - buffoonery, clowning, japery, harlequinade [archaic], prank

Derived forms: frivolities

Type of: craziness, folly, foolery, indulgence, lunacy, picayune [N. Amer, informal], piddler [informal], small beer [informal], small fry [informal], tomfoolery, trait, trifle, trivia, triviality

Antonym: earnestness

Encyclopedia: Frivolity