必不可少

1. Basic Information

• Pinyin: bì bù kě shǎo
• English Translation: Absolutely essential / Indispensable
• Idiom Composition: 「必」（Must or certainly）＋「不」（Not (negation)）＋「可」（Can or possible）＋「少」（To lack or be missing）
• Meaning: Absolutely necessary and impossible to do without; essential for the existence or success of something. It describes a state where something is so vital that the whole cannot function without it.

2. Detailed Meaning and Nuances

「必不可少」 contains the following nuances:

• Absolute Necessity: The structure uses a double negative—'not possible to lack'—to emphasize that the element is so critical that the entire system or goal would fail without it.
• Objective Requirements: Rather than expressing emotional attachment, this idiom is typically used to describe functional or logical requirements and objective conditions.

3. Usage

「必不可少」 is mainly used in the following contexts:

• Requirements and Conditions: Used when listing elements necessary for success or completion. This is the most common and versatile usage, frequently appearing in business or academic contexts.
  • Example:「对于想要精通外语的人来说，持续的练习是必不可少的。」
    （For those who want to master a foreign language, continuous practice is essential.）
• Daily Necessities: Used to refer to things one cannot live without, such as water, air, or modern technology.
  • Example:「手机已经成为现代人生活中必不可少的工具。」
    （Mobile phones have already become an indispensable tool in the lives of modern people.）
• Team or Organizational Roles: Used to evaluate a specific person who plays a vital role within a group or project.
  • Example:「他是我们团队中必不可少的一员，大家都非常依赖他。」
    （He is an indispensable member of our team, and everyone relies on him.）

Additional Examples:

1. 水和空气是人类生存必不可少的条件。
   （Water and air are essential conditions for human survival.）
2. 在这次谈判中，双方的诚意是达成协议必不可少的基础。
   （In these negotiations, sincerity from both sides is the indispensable foundation for reaching an agreement.）
3. 要想做出美味的菜肴，新鲜的食材是必不可少的。
   （To cook delicious food, fresh ingredients are absolutely necessary.）
4. 这种维生素是人体健康必不可少的营养素。
   （This vitamin is an essential nutrient for human health.）

4. Cultural Background and Notes

• Frequency of Use: This is a 'Common Idiom' (常用成语) used widely in both written and spoken Chinese. It does not carry the archaic weight of historical anecdotes, making it very natural for daily conversation.
• Grammatical Function: It primarily functions as a predicate (e.g., '...is 必不可少 (bì bù kě shǎo)') or as an adjective modifying a noun. While it is similar to 不可缺少 (bù kě quē shǎo), the inclusion of the character 必 (bì), meaning 'must,' makes the tone slightly more emphatic.

5. Similar and Opposite Idioms

• Similar Idioms:
  • 不可或缺 (bù kě huò quē): Indispensable; a slightly more formal and literary version of 必不可少 (bì bù kě shǎo), often preferred in formal writing.link
  • 至关重要 (zhì guān zhòng yào): Of vital importance; refers to something being a crucial turning point or key factor.link
• Opposite Idioms:
  • 可有可无 (kě yǒu kě wú): Optional or dispensable; something that does not matter whether it exists or not.
  • 多此一举 (duō cǐ yī jǔ): To do something unnecessary; a superfluous action that adds no value.
  • 无关紧要 (wú guān jǐn yào): Of no importance or consequence.link
  • 无足轻重 (wú zú qīng zhòng): Of no importance; insignificant.link

6. Summary

必不可少 (bì bù kě shǎo) is a high-frequency idiom used to describe anything that is vital or indispensable, ranging from abstract conditions to physical objects. It literally means 'must not be missing.' It is a versatile expression used in both formal business settings and casual daily life.