五官莫明于目是一个常用的成语，意为面容不明显，无法看出其真实意图或性格特征。这个成语源于古代小说《红楼梦》，形容贾宝玉一张面孔不显山不露水、不带一丝表情的脸。

这个成语的意义在日常生活中也有很多应用。比如，当我们遇到一个陌生人，如果他的面容不明显，我们就很难猜测他的性格、意图或情绪。甚至，在某些情况下，我们可能会感到不安或警惕。

在职场中，五官莫明于目的人也很常见。有些人看起来很平凡，但实际上他们可能很有才华、很聪明，也可能隐藏着某些意图或企图。对这样的人，我们需要时刻保持警惕，不要轻易相信他们的表面。

总之，五官莫明于目这个成语告诉我们，不能以貌取人，也不能轻信表面的东西。我们要学会通过各种方式去了解一个人，而不是仅仅依赖五官的外观。

Translation:

'Wu Guan Mo Ming Yu Mu' is a common Chinese idiom that means that one's facial features are not distinct enough to reveal their true intentions or personality traits. The idiom originates from the ancient Chinese novel 'Dream of the Red Chamber', where it describes the bland facial features of the main character Jia Baoyu.

This idiom has many applications in daily life. For example, when encountering a stranger with an undistinguished face, it can be difficult to guess their character, intentions, or emotions. In some cases, this can even lead to feelings of unease or suspicion.

In the workplace, it is also common to encounter people with undistinguished faces who may have hidden talents or motives. In such cases, it is important to remain vigilant and not easily trust what appears on the surface.

In summary, 'Wu Guan Mo Ming Yu Mu' reminds us not to judge people based on appearance alone and not to trust surface appearances. We must learn to understand people in different ways, rather than relying solely on their facial features.