ADJ-GRADED
(不分場合)亂開玩笑的，貧嘴的
If you say that someone is being facetious, you are criticizing them because they are making humorous remarks or saying things that they do not mean in a situation where they ought to be serious.
例句
The woman eyed him coldly. 'Don't be facetious,' she said.
婦人冷冷地看著他，說道：“別沒正經了。”