外亲内疏是指对外亲近，对内疏远的态度或行为。在人际关系中，外亲内疏可以表现为对外界的人和事物友好和热情，但对家人和亲密关系的人则保持一定的距离和冷漠。

How to pronounce: wài qīn nèi shū (wài - like "why", qīn - like "chin", nèi - like "nay", shū - like "shoe")

Usage: 外亲内疏可以用来形容一个人在不同关系中的态度差异。也可以用来指代一种保持适当距离的处世之道。

Example sentences:

1. 她对朋友总是很友善，但对家里人却有些冷淡，似乎是外亲内疏。

She is always friendly to her friends, but seems distant and cold towards her family, as if practicing the principle of "wài qīn nèi shū".

2. 在职场上，他与同事相处融洽，但私下里却很少与他们交往，似乎有意保持一种外亲内疏的态度。

In the workplace, he gets along well with his colleagues, but rarely socializes with them outside of work, as if intentionally maintaining a sense of "wài qīn nèi shū".

3. 他们夫妻俩的关系一直很和谐，但在公共场合却很少有亲密举动，似乎是遵循着外亲内疏的原则。

Their relationship has always been harmonious, but they rarely show any affection in public, as if following the principle of "wài qīn nèi shū".

4. 外亲内疏并不意味着冷漠或不关心，而是一种保持适当距离的方式。

"Wài qīn nèi shū" does not mean being cold or indifferent, but rather a way to maintain appropriate distance.

5. 在文化中，外亲内疏被认为是一种传统美德，可以帮助人们保持良好的人际关系。

In Chinese culture, "wài qīn nèi shū" is considered a traditional virtue that can help maintain good interpersonal relationships.

Synonyms and usage: 外热内冷 (wài rè nèi lěng) is a similar phrase that also describes the attitude of being warm and friendly towards outsiders, but cold and distant towards close relationships. It can be used interchangeably with "wài qīn nèi shū". Other possible synonyms include 外冷内热 (wài lěng nèi rè), 外善内恶 (wài shàn nèi è), and 外柔内刚 (wài róu nèi gāng).

Editor's summary: 外亲内疏是一种在人际关系中常见的态度，它可以帮助人们在不同关系中保持适当的距离，避免产生不必要的矛盾和。在文化中，外亲内疏被认为是一种传统美德，值得我们学习和借鉴。