“乌鸦嘴”，字面翻译是“crow's beak”，比喻嘴巴不吉利、说话不中听（mouth from which inauspicious remarks are uttered）。中国人认为乌鸦的叫声会带给人厄运（crow's cawing could bring people bad luck），因此常用“乌鸦嘴”来形容一个人讲话晦气，好事说不灵，坏事一说就灵。

例句：

你这张乌鸦嘴！

What improper remarks you've made!

别乌鸦嘴！

Don't say such shitty things!