flippant

在葬礼上开这样的玩笑显得很不庄重。

Making such a ___flippant joke at the funeral was inappropriate.

他在葬礼上轻率的笑话让所有人感到不适。

His ___flippant jokes at the funeral made everyone uncomfortable.

她那种漫不经心的态度让老师很头疼。

Her ___flippant attitude towards homework is frustrating the teacher.