Read the following excerpt from Susan B. Anthony by Alma Lutz: Every two weeks all through the winter, the fiddles played in the attic room and the boys and girls of the neighborhood danced the Virginia reel and their rounds and squares, while the three Quaker girls sat around the wall, watching and longing to join in the fun. Such frivolous entertainment in the home of a Quaker could not be condoned, and Daniel Anthony was not only severely censured by the Friends but read out of Meeting, "because he kept a place of amusement in his house." (pg. 13)

Based on the context, what does the word frivolous most likely mean?

serious
meaningful
unique
silly