Translation guide
The English word "brains" can refer to intelligence, the physical organ, or the person in charge. This guide helps you choose the right Japanese expression for each meaning.
Referring to someone's intelligence, cleverness, or mental capacity.
Literally 'head', but commonly used to mean intelligence or brains. Often used in phrases like 頭がいい (smart) or 頭が切れる (sharp).
彼は本当に頭がいい。
He's really smart.
あの子は頭の回転が速い。
That kid is quick-witted.
A more formal term for intelligence or intellectual ability. Often used in academic or technical contexts.
知能指数を測るテストを受けた。
I took a test to measure my IQ.
Intellectual power or mental capacity. Somewhat literary or formal.
彼の知力は並外れている。
His intellectual power is extraordinary.
Referring to the brain as a body part.
The standard word for the brain as an organ. Used in medical and everyday contexts.
脳の構造について勉強している。
I'm studying the structure of the brain.
脳に損傷を受けた。
He suffered brain damage.
Colloquial term for brains, often used in casual speech. Can sound slightly crude or humorous.
Referring to the mastermind or the smart person who devised a plan.
Literally 'black curtain', meaning the mastermind or brains behind a scheme. Often used in crime or conspiracy contexts.
事件の黒幕はまだ捕まっていない。
The brains behind the incident haven't been caught yet.
The ringleader or chief instigator. Formal and often used in legal or news contexts.
Can mean 'brains' in the sense of the intellectual leader of a group. Often used in phrases like 頭脳集団 (think tank).
Referring to animal brains used as food.
The same word for the organ, used when talking about eating brains. Often specified with the animal name, e.g., 豚の脳 (pig brains).
豚の脳を食べたことがありますか？
Have you ever eaten pig brains?
When saying someone is smart, avoid directly translating 'brains' as 脳 (のう). Use 頭 (あたま) instead. Saying 彼は脳がある sounds unnatural.
脳みそが飛び出るかと思った。
I thought my brains were going to pop out.
The mastermind fled abroad.
He's the brains of the team.