Translation guide
The concept of speed in Japanese can be expressed through nouns, adjectives, and verbs. The most common word is 速さ (hayasa), but the choice depends on whether you're talking about physical speed, quickness of action, or rate of progress.
To describe the speed of a vehicle, person, animal, or object in motion.
The most general noun for 'speed'. Used for physical movement.
The speed of this car is amazing.
The speed of the Shinkansen is 300 km/h.
Loanword from English, often used in sports, technology, or casual contexts. Can feel more dynamic.
Formal or technical term for speed or velocity. Common in physics, engineering, and official contexts.
To describe how quickly a person performs a task or reacts.
Also used for speed of action, not just movement.
To describe how fast something advances, such as technology, economic growth, or a process.
Can be used metaphorically for the pace of change.
To describe something as fast or high-speed.
The most common adjective for 'fast'. Used for both movement and action.
To express the action of accelerating or making something faster.
彼の投球のスピードは150キロを超える。
His pitching speed exceeds 150 km/h.
Please observe the speed limit.
彼の仕事の速さには驚いた。
I was surprised at the speed of his work.
Emphasizes agility, nimbleness, or quick reflexes. Often used for physical actions.
I was impressed by the cat's quickness.
Formal term for promptness or swiftness, often in business or official contexts.
Promptness of response is required.
技術の進歩の速さは目を見張るものがある。
The speed of technological progress is astonishing.
Often used in business or casual talk about pace.
The progress speed of this project is too slow.
Loanword meaning 'pace'. Often used for work, study, or life rhythm.
You can study at your own speed.
This train is very fast.
He is fast at his work.
Means 'high-speed', often used as a prefix or in compound nouns.
I drove on the expressway (high-speed road).
Transitive verb: to speed something up.
I increased the car's speed.
Intransitive verb: to become faster.
The wind suddenly sped up.
Common phrase meaning 'to increase speed'.
Please speed up a little more.
He is early in the morning.
スピード is a loanword and can sound casual or marketing-like. In formal writing, prefer 速度 or 速さ.
He finished the work with amazing speed.