Translation guide
The English word 'rapid' describes something happening quickly or at a fast pace. In Japanese, the most common equivalent is 速い (hayai), but there are also more specific terms for rapid growth, rapid increase, rapid progress, and rapid-fire speech or action. This guide covers the main ways to express 'rapid' depending on the context.
Describing something that moves or happens quickly, such as a rapid movement, rapid breathing, or a rapid pace.
The most common and versatile word for 'fast' or 'rapid'. Can be used for physical speed, quick actions, or rapid changes. Note that 速い is for speed, while 早い (also はやい) is for 'early'.
A more formal adjective meaning 'rapid' or 'swift', often used for changes, growth, or developments. Common in news and technical contexts.
急速な技術の進歩
rapid technological progress
病気が急速に悪化した。
The illness worsened rapidly.
Means 'sudden and rapid', often implying a sharp or drastic change. Used for increases, decreases, or shifts.
急激な温度変化
a rapid change in temperature
人口が急激に増えた。
The population increased rapidly.
Means 'rapid' in the sense of 'prompt' or 'speedy', often used for responses, actions, or services. Implies efficiency.
迅速な対応をお願いします。
Please respond rapidly.
彼は迅速に行動した。
He acted rapidly.
Describing something that grows, expands, or multiplies quickly, such as rapid economic growth or a rapid rise in numbers.
Literally 'rapid growth'. Commonly used for businesses, economies, or personal development.
その会社は急成長を遂げた。
The company achieved rapid growth.
Means 'rapid increase' or 'surge'. Used for numbers, cases, or quantities.
感染者が急増している。
Infections are increasing rapidly.
Means 'rapid rise' or 'sharp increase', often used in economic contexts like stock prices or sales.
Describing quick progress in a project, skill, or field, such as rapid improvement or rapid development.
A common phrase for 'rapid progress', especially in technology or science.
AIの急速な進歩には驚かされる。
The rapid progress of AI is astonishing.
Means 'dramatic' or 'rapid' advancement, often implying a leap forward. Used for progress, growth, or improvement.
彼の日本語力は飛躍的に向上した。
His Japanese ability improved rapidly.
Describing something done quickly and continuously, like rapid-fire questions or rapid typing.
Literally 'arrow-after-arrow quick'. Used for rapid-fire questions, actions, or attacks. Often in the form 矢継ぎ早に.
記者が矢継ぎ早に質問した。
The reporter asked rapid-fire questions.
Means 'consecutive' or 'one after another', often implying rapid succession. Used for events, questions, or actions.
立て続けに事件が起きた。
Incidents occurred in rapid succession.
Specifically for rapid speech. 早口 means 'fast-talking'.
彼の早口の説明はわかりにくい。
His rapid explanation is hard to understand.
速い (hayai) is the general word for 'fast' and can be used in everyday conversation. 急速 (kyūsoku) is more formal and often used for processes or changes. 急激 (kyūgeki) implies a sudden and sharp change, often with a nuance of intensity or danger.
The loanword ラピッド (rapiddo) exists but is not commonly used in natural Japanese except in some compound terms like ラピッドファイア (rapid fire) in gaming contexts. Stick to native Japanese words for most situations.
その川は流れが速い。
The river has a rapid current.
市場は急速に変化している。
We are seeing rapid changes in the market.
株価が急伸した。
Stock prices rose rapidly.