Synonyms for Frivolity (same or very similar meaning)
WordNet sense 1 (the trait of being frivolous; not serious or sensible):
frivolousnessWordNet sense 2 (something of little value or significance):
bagatelle, fluff, fripperyWordNet sense 3 (acting like a clown or buffoon):
buffoonery, japery, prank, clowning, harlequinadeFrom the ODE community, based on WordNetadd/edit