Translation guide
The English word 'rational' covers a range of meanings from logical thinking to reasonable behavior. In Japanese, different words and patterns are used depending on whether you mean 'based on reason rather than emotion', 'sensible and practical', or 'able to think clearly'. This guide helps you choose the most natural expression.
Describing a decision, argument, or approach that is logical and not influenced by feelings.
The most common and versatile word for 'rational' in the sense of logical, efficient, and based on reason. Used for decisions, systems, and thinking.
His judgment is rational.
I'm looking for a rational explanation.
Emphasizes the use of reason and intellect, often contrasted with emotion or instinct. Slightly more formal or philosophical.
Let's discuss this rationally, without getting emotional.
Literally 'in accordance with reason'. A natural phrase meaning something is logical or makes sense.
His proposal is rational.
Describing a person, action, or choice that is based on good judgment and practicality.
Means having good sense or discretion. Often used for people who make sound, practical decisions.
He is a rational person.
Means wise or sensible. Often used for decisions or actions that are prudent and well-considered.
That's a rational choice.
Also works for practical, efficient choices, but leans more toward logical consistency.
Describing a person's mental state as calm, lucid, and capable of reasoning.
Referring to numbers that can be expressed as a fraction.
The mathematical term for 'rational number'. Not used in everyday language.
Please explain the difference between rational and irrational numbers.
The katakana word ラショナル is sometimes used in technical contexts (e.g., 'rational统一'), but it is not a natural way to express the general concept of 'rational' in Japanese. Stick to the native Japanese terms above.
合理的 (gōriteki) focuses on logical consistency and efficiency, often used for systems, plans, and decisions. 理性的 (riseiteki) emphasizes the use of reason and intellect, often in contrast to emotion. For 'rational thinking', both can work, but 合理的 is more common in everyday contexts.
合理的な判断を下した。
I made a rational decision.