behaviour that is silly and not serious, or things that are silly and not important

You shouldn't treat such a serious subject with frivolity. 对待如此严肃的话题不能敷衍轻视。

I'm far too busy to waste time on frivolities like going to the cinema. 我忙得不可开交，不会把时间浪费在看电影之类无聊的事上。