Translation guide
The English word "keen" has several distinct meanings. This guide covers the most common uses for learners: being eager or enthusiastic, having a sharp mind or senses, and describing intense emotions or competition. It also notes less common uses like sharp blades or low prices.
Expressing strong interest, willingness, or desire to do something.
Attach to the verb stem to express 'want to do'. This is the most direct and common way to express keenness to do something.
私は日本に行きたいです。
I'm keen to go to Japan.
彼は新しいプロジェクトを始めたがっている。
He is keen to start a new project.
Means 'to be enthusiastic' or 'eager' about a suggestion or plan. Often used when someone is keen on an idea.
彼はその提案に乗り気だ。
He is keen on the proposal.
彼女はあまり乗り気じゃなさそうだ。
She doesn't seem very keen.
Means 'enthusiastic' or 'zealous'. Suitable for describing a keen learner, supporter, etc.
彼は熱心な生徒だ。
He is a keen student.
To be full of energy and eagerness, often before an event. 'Raring to go'.
子供たちは遠足の前日から張り切っていた。
The children were keen and excited the day before the school trip.
Describing acute intelligence, perception, or highly developed senses.
The most common word for 'sharp' in the sense of keen senses, intellect, or insight. Works for eyesight, hearing, intuition, analysis, etc.
彼は鋭い観察力を持っている。
He has keen powers of observation.
犬は鋭い嗅覚を持っている。
Dogs have a keen sense of smell.
Means 'sensitive'. Used for keen senses or emotional sensitivity. Slightly different nuance from 鋭い, focusing on responsiveness to stimuli.
彼女は音に敏感だ。
She has keen hearing. (lit. She is sensitive to sounds.)
A set phrase meaning 'to have keen intuition' or 'sharp instincts'.
彼は勘が鋭いから、すぐに嘘を見抜く。
He has keen intuition, so he spots lies immediately.
Describing strong feelings, deep interest, or fierce rivalry.
The basic word for 'strong'. Can modify nouns like 興味 (interest) or 関心 (concern) to mean 'keen interest'.
彼は歴史に強い興味を持っている。
He has a keen interest in history.
Means 'intense' or 'fierce'. Used for keen competition, rivalry, or emotions like jealousy.
Means 'keen' in the sense of 'acute' or 'poignant', often for emotional pain or awareness. Literary/formal.
彼は痛切な悲しみを感じた。
He felt a keen sorrow.
Describing a physically sharp cutting edge.
Also used for physical sharpness of blades, claws, etc. Same word as for mental sharpness.
そのナイフは鋭い刃を持っている。
The knife has a keen blade.
A common phrase meaning 'cuts well', i.e., very sharp. More colloquial than 鋭い for blades.
この包丁はよく切れる。
This kitchen knife is very keen.
Describing a very competitive or low price. (British English usage)
Means 'competitive price'. Used in business contexts. The English 'keen price' is British; in Japanese, 'competitive' is more natural.
当社は競争力のある価格を提供します。
We offer keen prices.
The English phrase 'keen on' (liking something or someone) does not have a single direct equivalent. Use 好き (like) or 興味がある (have interest) instead. Avoid literal translations like 〜に熱心だ for casual likes.
彼はサッカーが好きだ。
He is keen on soccer.
彼女は彼に興味がある。
She is keen on him.
鋭い (surudoi) implies active sharpness or acuteness (keen eyesight, keen mind). 敏感 (binkan) implies passive sensitivity or susceptibility (sensitive to cold, sensitive hearing). For 'keen senses', 鋭い is usually better unless emphasizing reaction to stimuli.
その考えにはあまり乗り気じゃない。
I'm not too keen on that idea.
彼女は細かいところにまで目が届く。
She has a keen eye for detail.
Natural Japanese idiom meaning 'her eyes reach even the small details'.
その会社は激しい競争に直面している。
The company faces keen competition.