alien

Compared meaning: a person from another country (noun).

比较义项：来自另一个国家的人（名词）。

• alien 本词

  A formal, often legal or bureaucratic term for a person from another country, typical of immigration law and official documents (e.g. 'resident alien'); can sound cold or impersonal in everyday speech.

  指来自另一个国家的人的正式说法，常用于移民法律或官方文件中（如“resident alien 常住外侨”），日常口语中使用会显得生硬、公事化。

  Non-citizens are officially classified as resident aliens for tax purposes.

  非公民在纳税方面被官方归类为常住外侨。

• foreigner

  The plain, everyday word for a person from another country, used in ordinary conversation with no legal or official tone.

  指来自另一个国家的人的普通日常用词，用于一般口语交流，没有法律或官方色彩。

  As a foreigner, she needed a visa to work here.

  作为一名外国人，她需要签证才能在这里工作。

Alien and foreigner both mean a person from another country. Alien is formal, common in legal or official language, such as immigration documents. Foreigner is the plain, everyday word used in ordinary conversation. Not compared: alien meaning a being from outer space.

这两个词在“外国人”这个意思上很接近，但alien是正式、常见于法律或官方语境的说法，语气偏冷淡、公事化；foreigner是日常口语中最自然、中性的说法。这里不比较alien的“外星人”义项。

Compared meaning: from a foreign country, different from one's own (adjective).

比较义项：来自异国、与本国不同的（形容词）。

• foreign

  The everyday, neutral term for anything from another country; used broadly for people, languages, policies and goods, with no special emotional color.

  日常中性词，泛指来自其他国家的人、语言、政策或商品，不带特殊感情色彩。

  Foreign students make up a third of the university's population.

  外国留学生占该大学学生总数的三分之一。

• alien 本词

  More formal and stronger than foreign; suggests something strange, unfamiliar or not belonging, often with a negative or unsettling feel; used for environments, customs or ideas.

  比foreign更正式、语气更强，暗示某事物陌生、不熟悉、格格不入，常带负面或令人不安的感觉，多用于描述环境、习俗或观念。

  The desert felt like an alien landscape to the sailors.

  对水手们来说，这片沙漠如同一片陌生怪异的异域景观。

• exotic

  Emphasizes excitement and novelty in something from a distant foreign country; used positively for food, plants or places that seem colorful and unusual.

  强调来自遥远异国的新奇感和吸引力，常用于描述食物、植物或地方，带有多彩有趣的正面色彩。

  The market sold exotic spices imported from Southeast Asia.

  市场上出售从东南亚进口的异域香料。

These three mean from another country, but differ in tone. Foreign is neutral and common. Alien is stronger and formal, suggesting something strange or unsettling. Exotic is positive, describing something excitingly unusual, like food or plants. Not compared: alien meaning a being from outer space.

这三个词都能表示“来自外国的”，但语气和用法不同：foreign最中性、最常用；alien语气更强、更正式，常带陌生或令人不安的意味；exotic强调新奇有趣的异域色彩，多用于食物、植物等。这里不比较alien作名词表示“外星人”的用法，也不比较alien to sb这一固定搭配。