He did not like to combine frivolity with the serious business of hunting.
As it is now, war is the favorite pastime of the idle and frivolous.
With the enemy’s approach to Moscow, the Moscovites’ view of their situation did not grow more serious but on the contrary became even more frivolous, as always happens with people who see a great danger approaching.
And when he realized that people might not be aware of his happiness, he pitied them with his whole heart and felt a desire somehow to explain to them that all that occupied them was a mere frivolous trifle unworthy of attention.
"Youth, frivolity…. well, God be with him," thought he, relishing his own goodness of heart, "but it must be brought to a head.
She thought her too fashionably dressed, frivolously gay and vain.
There are no more uses of "frivolous" in the book.