How to say "reaction" in Japanese
Choosing the right word
- 反応はんのうnoun, suru verb, intransitive verbThe default word for a reaction in the sense of a response to something — a stimulus, an event, or another person's words or actions; it also covers scientific senses such as chemical reactions.
- nounThe loanword, typically for a person's outward, expressive reaction — how they visibly or audibly respond in the moment, as to a surprise, a joke, or a performance.
- 反動はんどうnounNot the everyday 'response' sense: 反動 is a force or movement in the opposite direction — the recoil or kick of a gun, or a backlash against a preceding trend or policy.
- 戻りもどりnounEssentially 'return' or 'recovery'; its 'reaction' sense is a rebound — a price or value recovering after a fall — so it is seldom the word you want for a reaction in the everyday sense.
- 反作用はんさようnounThe term for 'reaction' as the counterpart of an action — in physics, action and reaction — or, by extension, an opposing effect produced in return; not a word for a person's response to events.
Use 反応 for a response to a stimulus or event and 「リアクション」 for an expressive personal reaction; 反動 is a recoil or backlash, 反作用 the physical counterpart of an action, and 「戻り」 a recovery after a fall.
Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only
Japanese equivalents
See also
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