费 (fèi): This character means “to spend,” “to consume,” or “to use up.” It's the same character used in words like `费用 (fèiyòng)` for expenses or `浪费 (làngfèi)` for waste. Here, it implies an expenditure of a resource.
脑子 (nǎozi): This word means “brain” or “mind.” `脑 (nǎo)` is the character for brain, and `子 (zi)` is a common noun suffix that doesn't change the meaning.
When combined, `费脑子 (fèi nǎozi)` literally translates to “expend the brain,” a vivid and intuitive way to say that an activity is draining your mental energy.
While not a deep philosophical term, `费脑子` reflects a common, everyday perspective in Chinese culture. In a society that highly values education, problem-solving, and intellectual capability, acknowledging that a task is `费脑子` can be both a complaint and a sign of respect for its complexity.
A good Western comparison is the phrase “it's a real headache,” but they are not identical.
“A headache” often carries a stronger connotation of annoyance, frustration, and something you wish to avoid. For example, “Dealing with customer service was a real headache.”
`费脑子` focuses more purely on the cognitive load. A task can be `费脑子` but still enjoyable or rewarding, like a complex board game or a challenging programming task. While it can certainly be used to complain, it doesn't automatically imply frustration in the same way “headache” often does. It simply states a fact: “This requires a lot of thinking.”
`费脑子` is a highly versatile and informal term used constantly in daily life.
Formality: Highly informal and colloquial. Perfect for conversations with friends, family, and colleagues, but you would likely choose a more formal word like `复杂 (fùzá)` (complex) in a formal written report.
Connotation: Generally neutral-to-negative. It's often used as a mild complaint about the difficulty or complexity of a task. However, it can also be used neutrally to simply describe the nature of a job or activity.
You'll hear it in many contexts:
Work & Study: “这个项目的计划太费脑子了。” (Planning for this project is so mentally taxing.)
Social Situations: “搞清楚他们家的人际关系，真费脑子。” (Figuring out their family's interpersonal relationships is a real brain-drain.)
Hobbies & Daily Life: “我觉得下棋比打牌费脑子。” (I think playing chess is more brain-racking than playing cards.)
As a simple response: When someone explains a complicated plan, you can just sigh and say, “太费脑子了！” (That's too much work for my brain!)