Meaning:

    “乌鸦” is “crow” or “raven,” and “嘴” is “mouth.” Chinese believe the crow cawing could bring bad luck to people. So, anyone who has a jinxing mouth is said to have a “crow’s mouth,” a persona non grata in any conversation or discussion.

    Example:

    A: 明天可千万别下雨，我们筹划了很久的足球赛要开始了。

    Míngtiān kě qiānwàn bié xiàyǔ, wǒmen chóuhuà le hěn jǐu de zúqíusài yào kāishǐ le。

    For God’s sake, please don’t rain tomorrow. The soccer games we’ve been planning for some time will finally open.

    B: 可是天气预报说这两天有雨呢，今天没下，说不准明天会下。现在的天气预报还挺准的。

    Kěshì tiānqì yùbào shuō zhè liǎngtiān yǒu yǔ ne, jīntiān méi xià, shuōbùzhǔn míngtiān huì xià。Xiànzài de tiānqì yùbào hái tǐng zhǔn de。

    But the weather forecast says it will rain these two days. If it doesn’t rain today, perhaps it will rain tomorrow. The weather forecast nowadays is pretty good.

    A: 你别乌鸦嘴了。

    Nǐ bié wūyāzuǐ le。

    Shut up your jinxing mouth.