Translation guide
The English verb 'prevent' is used to express stopping something from happening, hindering an action, or keeping someone from doing something. In Japanese, there is no single direct equivalent; the best choice depends on whether you are stopping an event, blocking an action, or restraining a person. Common strategies include using verbs like 防ぐ (physically or metaphorically block), 妨げる (hinder/interfere), or causative patterns with させない (not let someone do).
To take measures so that something bad does not happen (accident, disease, war, etc.)
The most common and versatile verb for preventing something undesirable. Used for concrete and abstract threats.
事故を防ぐために、安全対策を強化した。
We strengthened safety measures to prevent accidents.
感染拡大を防ぐには手洗いが重要だ。
Handwashing is important to prevent the spread of infection.
Specifically for preventing disease or health problems through proactive measures.
インフルエンザを予防するためにワクチンを接種した。
I got vaccinated to prevent the flu.
Emphasizes preventing something before it happens; 'nip in the bud'.
トラブルを未然に防ぐためのチェックリストを作成した。
We created a checklist to prevent problems before they occur.
To keep a person from carrying out an action, often by creating an obstacle or using authority.
Causative negative form: 'not let/make someone do'. Natural for preventing a person's action.
彼が危険な場所に行くのを防いだ。
I prevented him from going to the dangerous place.
親は子供にジャンクフードを食べさせないようにしている。
Parents try to prevent their children from eating junk food.
To hinder or obstruct someone's action. Often implies interference.
To forcibly stop an action or plan, often used in formal or news contexts.
警察はテロ計画を阻止した。
The police prevented the terrorist plot.
To create a condition where an event cannot occur, often through rules, design, or inherent properties.
A versatile phrase meaning 'make sure not to...' or 'arrange so that... doesn't happen'. Very common in daily speech.
忘れないようにメモを取った。
I took notes to prevent forgetting.
風邪を引かないように暖かくして寝た。
I slept warmly to prevent catching a cold.
Also works here, especially for physical prevention.
Literal 'make impossible'. Used in technical or formal explanations.
このシステムは不正アクセスを不可能にする。
This system prevents unauthorized access.
English 'prevent someone from doing' often becomes awkward if translated word-for-word. Instead of trying to map 'prevent' directly, use causative negative (させない) or 〜ないようにする patterns. For example, 'I prevented him from leaving' is naturally 彼を行かせなかった or 彼が行くのを止めた, not a direct translation with 防ぐ.
彼が行くのを止めた。
I stopped him from going. (natural equivalent of 'prevented')
防ぐ (fusegu) is the general term for preventing something bad. 妨げる (samatageru) focuses on hindering or interfering with an ongoing action or process. 阻止する (soshi suru) is stronger, implying active and often forceful prevention of a planned action. Use 防ぐ for most cases; 妨げる when obstruction is key; 阻止する for formal/forceful prevention.
騒音が彼の集中を妨げた。
The noise prevented him from concentrating.
This coating prevents rust.