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.
rapid growth
rapid increase
rapid progress
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.
rapid technological progress
Means 'sudden and rapid', often implying a sharp or drastic change. Used for increases, decreases, or shifts.
a rapid change in temperature
Means 'rapid' in the sense of 'prompt' or 'speedy', often used for responses, actions, or services. Implies efficiency.
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.
Describing quick progress in a project, skill, or field, such as rapid improvement or rapid development.
Describing something done quickly and continuously, like rapid-fire questions or rapid typing.
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 car is fast.
The river has a rapid current.
My pulse is rapid.
The illness worsened rapidly.
人口が急激に増えた。
The population increased rapidly.
Please respond rapidly.
He acted rapidly.
The company achieved rapid growth.
Means 'rapid increase' or 'surge'. Used for numbers, cases, or quantities.
Infections are increasing rapidly.
Means 'rapid rise' or 'sharp increase', often used in economic contexts like stock prices or sales.
Stock prices rose rapidly.
The rapid progress of AI is astonishing.
Means 'dramatic' or 'rapid' advancement, often implying a leap forward. Used for progress, growth, or improvement.
His Japanese ability improved rapidly.
The reporter asked rapid-fire questions.
Means 'consecutive' or 'one after another', often implying rapid succession. Used for events, questions, or actions.
Incidents occurred in rapid succession.
Specifically for rapid speech. 早口 means 'fast-talking'.
His rapid explanation is hard to understand.
急速に発展する都市
a rapidly developing city
a rapid appreciation of the yen
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.
We are seeing rapid changes in the market.