flippant
adjective uk/ˈflɪp.ənt/ us/ˈflɪp.ənt/ (UK informal flip)
轻率的；浮夸的
not serious about a serious subject, in an attempt to be funny or to appear clever
a flippant remark/attitude 轻率的言论／态度
It's easy to be flippant, but we have a serious problem to deal with here. 油嘴滑舌容易，但我们有正经问题要解决。
I think she just thought I was being flippant. 我想她只是认为我态度轻率。