levity

在严肃的会议之后，他的玩笑带来了一些轻松的气氛。

After the serious meeting, his joke brought some much-needed ___levity.

他在严肃会议上的不合时宜的轻浮行为让所有人都皱起了眉头。

His inappropriate ___levity during the serious meeting made everyone frown.