有害 in 30 Seconds
- Harmful; causing damage or injury.
- Used for dangerous substances, actions, or environments.
- Often seen in warnings and safety information.
- Implies a significant negative impact.
The Japanese adjective 有害 (yūgai) translates to 'harmful' or 'damaging' in English. It describes something that can cause injury, damage, or negative effects. This word is used in a variety of contexts, from warnings about physical dangers to discussions about the detrimental effects of certain substances, behaviors, or policies. It signifies a clear negative impact that should be avoided or addressed.
- Usage Contexts
- You'll often see or hear 有害 used in official warnings, safety guidelines, environmental reports, and discussions about health and well-being. For instance, it might appear on labels of potentially dangerous products, in public health announcements about pollution, or in articles discussing the negative impacts of social media on mental health. It's a formal and direct way to convey that something is detrimental.
- Nuance
- While 有害 directly means 'harmful,' it carries a weight that suggests a more significant or lasting negative effect than a simple inconvenience. It's not typically used for minor annoyances but rather for things that pose a genuine risk or cause substantial damage. The degree of harm can vary, but the core meaning remains consistent: something that is detrimental.
この化学物質は有害なガスを発生させる可能性があります。 (Kono kagakubusshitsu wa yūgai na gasu o hassei saseru kanōsei ga arimasu.)
喫煙は健康に有害です。 (Kitsuen wa kenkō ni yūgai desu.)
- Beyond Physical Harm
- While physical harm is a primary association, 有害 can also refer to psychological, social, or environmental damage. For example, exposure to excessive violence in media could be considered 有害 for children. Similarly, certain business practices might be deemed 有害 to the local economy. The context will clarify the specific type of harm being discussed.
この食品添加物は有害である疑いがある。 (Kono shokuhin tenkabutsu wa yūgai de aru utagai ga aru.)
The adjective 有害 (yūgai) is typically used in a few common grammatical structures. It often modifies a noun directly, or it can be used with the copula です (desu) or である (de aru) to make a statement. Understanding these patterns will help you use and understand 有害 effectively in various situations.
- Modifying Nouns Directly
- One of the most common ways to use 有害 is by placing it before a noun, often with the particle な (na). This structure describes the noun as being harmful. For example, 有害な物質 (yūgai na busshitsu) means 'harmful substance,' and 有害な影響 (yūgai na eikyō) means 'harmful influence.' This is a straightforward way to convey the negative quality of something.
この地域には有害な植物が多く自生しています。 (Kono chiiki ni wa yūgai na shokubutsu ga ōku jisei shite imasu.)
- Making Statements with です (desu)
- To make a declarative statement about something being harmful, you can use 有害です (yūgai desu). This is a polite and common way to express that something is harmful. For instance, この水は有害です (Kono mizu wa yūgai desu) means 'This water is harmful.' This form is suitable for most general situations and conversations.
長時間の紫外線暴露は皮膚に有害です。 (Chōjikan no shigaisen hokuro wa hifu ni yūgai desu.)
- Using である (de aru) for Formal Statements
- 有害である (yūgai de aru) is a more formal way of stating that something is harmful. This construction is often found in written materials, official reports, academic papers, and formal speeches. It carries a more definitive and objective tone. For example, その行為は社会的に有害であると判断された (Sono kōi wa shakaiteki ni yūgai de aru to handan sareta) means 'That act was judged to be socially harmful.' This is the preferred form in more serious or technical contexts.
未成年者への不適切な情報提供は有害である可能性があります。 (Miseinensha e no futekisetsu na jōhō teikyō wa yūgai de aru kanōsei ga arimasu.)
この製品は子供の手の届かない場所に保管してください。有害な成分が含まれています。 (Kono seihin wa kodomo no te no todokanai basho ni hokan shite kudasai. Yūgai na seibun ga fukumarete imasu.)
- Contextual Variations
- The choice between 有害です and 有害である often depends on the formality of the situation. In everyday conversation, 有害です is more common. In written or formal settings, 有害である is preferred. Both clearly convey the meaning of being harmful.
You will encounter the word 有害 (yūgai) in a variety of real-world scenarios, particularly in situations where warnings, safety, or potential negative impacts are being discussed. Its usage spans formal announcements to more casual, yet serious, conversations.
- Public Safety Announcements and Warnings
- Official warnings from government agencies, police, or emergency services frequently use 有害. You might hear it in announcements about natural disasters warning of 有害なガス (yūgai na gasu - harmful gases) released, or about contaminated water sources being 有害 (yūgai). Signs in public spaces might warn of 有害な生物 (yūgai na seibutsu - harmful organisms) or areas with 有害な放射線 (yūgai na hōshasen - harmful radiation).
注意：この池の水は有害です。飲まないでください。 (Chūi: Kono ike no mizu wa yūgai desu. Nomanaide kudasai.)
- Product Labels and Safety Information
- When purchasing products, especially chemicals, medicines, or certain foods, you'll often find warnings using 有害. Labels might state 有害な成分が含まれています (yūgai na seibun ga fukumarete imasu - contains harmful ingredients) or 子供には有害 (kodomo ni wa yūgai - harmful to children). This is a crucial term for consumer safety.
この農薬は環境に有害であるため、使用が制限されています。 (Kono nōyaku wa kankyō ni yūgai de aru tame, shiyō ga seigen sarete imasu.)
- Environmental and Health Discussions
- News reports, documentaries, and public health campaigns discussing pollution, disease, or unhealthy lifestyles will use 有害. For example, discussions about air pollution might refer to 有害な粒子 (yūgai na ryūshi - harmful particles), or health advice might state that 有害な食品添加物 (yūgai na shokuhin tenkabutsu - harmful food additives) should be avoided.
受動喫煙は非喫煙者にとっても有害です。 (Judō kitsuen wa hikitsuen-sha ni totte mo yūgai desu.)
- Academic and Technical Writing
- In scientific papers, research articles, and technical manuals, 有害 is used to describe substances, conditions, or effects that are detrimental. This is where you are most likely to see the formal 有害である (yūgai de aru) construction.
この地域での過剰な農薬使用は、土壌に有害な影響を与えています。 (Kono chiiki de no kajō na nōyaku shiyō wa, dojō ni yūgai na eikyō o ataete imasu.)
While 有害 (yūgai) is a relatively straightforward adjective, learners can sometimes make mistakes in its usage, particularly concerning its formality and the scope of its meaning. Being aware of these common pitfalls can help you use the word more accurately and naturally.
- Overusing it for Minor Issues
- One common mistake is using 有害 to describe something that is merely inconvenient or slightly annoying. 有害 implies a significant negative impact, damage, or danger. For minor annoyances, words like 迷惑 (meiwaku - troublesome) or 不便 (fuben - inconvenient) would be more appropriate. For example, saying a slow internet connection is 有害 would be an exaggeration; it's simply 不便.
❌ 渋滞は有害です。(Jūtai wa yūgai desu.)
✅ 渋滞は迷惑です。(Jūtai wa meiwaku desu.)
- Confusing with Similar Concepts
- Learners might confuse 有害 with words that describe something unpleasant or dangerous in a less direct way. For instance, 危険 (kiken - dangerous) is related but focuses more on the potential for immediate harm or risk, while 有害 emphasizes the damaging effect itself. Something can be 危険 without necessarily being 有害 in the long term, and vice versa. For example, a steep cliff is 危険, but a slow-acting poison is 有害.
❌ この薬は有害な匂いがする。(Kono kusuri wa yūgai na nioi ga suru.)
✅ この薬は危険な匂いがする。(Kono kusuri wa kiken na nioi ga suru.)
- Incorrect Grammatical Attachment
- As a na-adjective, 有害 requires the particle な (na) when it directly modifies a noun. Forgetting this particle is a common grammatical error for learners. For instance, saying 有害物質 (yūgai busshitsu) instead of 有害な物質 (yūgai na busshitsu) is incorrect. Similarly, when used predicatively with です (desu) or である (de aru), no particle is needed, but incorrectly adding one can occur.
❌ この化学薬品は有害ガスを発生します。(Kono kagaku yakuhin wa yūgai gasu o hassei shimasu.)
✅ この化学薬品は有害なガスを発生します。(Kono kagaku yakuhin wa yūgai na gasu o hassei shimasu.)
- Using it in informal spoken contexts inappropriately
- 有害 is generally a formal or semi-formal word. While it can be used in spoken Japanese, it's less common in very casual, everyday chat among close friends unless the topic is serious. Using it for something trivial in a casual setting might sound overly dramatic or stiff. For more casual conversations about negative things, other expressions might be preferred.
While 有害 (yūgai) is a precise term for 'harmful,' Japanese offers several other words and phrases that convey similar or related meanings, each with its own nuance and typical usage. Understanding these alternatives will enrich your vocabulary and allow for more precise expression.
- 危険 (kiken) - Dangerous
- Meaning: Dangerous; risk.
Comparison: 危険 focuses on the potential for immediate harm or risk. Something can be 危険 (e.g., a steep cliff) without necessarily being 有害 in the sense of causing damage over time (though falling off it would be). 有害 emphasizes the damaging effect itself, which might be immediate or gradual.
Example: 危険な場所 (kiken na basho - dangerous place) vs. 有害な物質 (yūgai na busshitsu - harmful substance). A fire is 危険, and the smoke it produces can be 有害.
- 損害 (songai) - Damage; Loss
- Meaning: Damage, loss, injury.
Comparison: 損害 is primarily a noun referring to the result of harm or damage, often in a financial or material sense. 有害 is an adjective describing the cause or quality of being harmful. You might say a certain action caused 損害 (damage), and that the action itself was 有害 (harmful).
Example: 自然災害は経済に大きな損害を与える可能性がある。 (Shizen saigai wa keizai ni ōkina songai o ataeru kanōsei ga aru - Natural disasters can cause significant damage to the economy.) The elements causing the disaster could be described as 有害.
- 悪影響 (akueikyō) - Negative Influence/Effect
- Meaning: Negative influence, adverse effect.
Comparison: 悪影響 is a noun that specifically refers to a bad influence or consequence. It's often used when discussing psychological, social, or behavioral impacts. 有害 is broader and can encompass physical damage as well. 悪影響 is a type of 有害 effect.
Example: 過度なゲームは子供の成長に悪影響を及ぼすことがある。(Kado na gēmu wa kodomo no seichō ni akueikyō o oyobosu koto ga aru - Excessive gaming can have a negative effect on children's development.)
- 不健全 (fukenzen) - Unhealthy
- Meaning: Unhealthy; not sound.
Comparison: 不健全 is used to describe things that are not good for health, often in a lifestyle or moral sense. It's less direct about causing specific damage than 有害. For example, a diet high in sugar is 不健全, and consuming too much of it could lead to 有害な health conditions.
Example: 彼は不健全な生活を送っている。(Kare wa fukenzen na seikatsu o okutte iru - He is leading an unhealthy lifestyle.)
- 毒性 (dokusei) - Toxicity
- Meaning: Toxicity; poisonousness.
Comparison: 毒性 is a noun referring to the degree to which something is poisonous. It's a specific type of harm. A substance with high 毒性 is certainly 有害. 有害 is the broader adjective describing the harmful nature, which could stem from toxicity or other causes.
Example: この物質の毒性は非常に高い。(Kono busshitsu no dokusei wa hijō ni takai - The toxicity of this substance is very high.)
How Formal Is It?
"本製品は、環境に有害である可能性のある成分を含んでおります。"
"この地域では、有害な植物が多く見られます。"
"その食べ物、体に有害だよ、気をつけて。"
"このおもちゃには、小さな部品があって、小さい子には有害かもしれないよ。"
Fun Fact
The kanji 害 (gai) can be broken down further. The top part resembles a trap or a net, and the bottom part can represent a mouth or a person. This imagery might suggest something being caught or ensnared, leading to harm. In ancient Chinese inscriptions, 害 was depicted as a person with a sword or a sharp object piercing them, clearly indicating harm.
Pronunciation Guide
- Pronouncing 'yuu' too short, making it sound like 'yuh-guy'.
- Incorrectly stressing the first syllable.
- Confusing the 'gai' sound with other sounds.
Difficulty Rating
Understanding 'yūgai' in reading is generally straightforward as it's often used in clear warning contexts. However, in more nuanced or academic texts, understanding the specific type of harm or its implications might require a higher level of comprehension.
Using 'yūgai' correctly in writing requires attention to grammatical particles (like 'na') and choosing the appropriate register (e.g., 'desu' vs. 'de aru'). Overuse or misuse for minor issues can sound unnatural.
Speaking with 'yūgai' is common in formal warnings or serious discussions. In casual conversation, it might sound too strong unless the topic genuinely warrants it. Choosing the right context is key.
Recognizing 'yūgai' in spoken Japanese is usually easy due to its clear meaning and often serious context. The challenge lies in understanding the implications of what is described as 'yūgai'.
What to Learn Next
Prerequisites
Learn Next
Advanced
Grammar to Know
Na-Adjectives and the particle 'na'
Na-adjectives like 有害 (yūgai) require the particle な (na) when they directly modify a noun. For example, 有害な物質 (yūgai na busshitsu - harmful substance). Without 'na', it would be grammatically incorrect.
Using 'desu' and 'de aru' for predicative use
When used at the end of a sentence to describe the subject, na-adjectives are followed by です (desu) for politeness or である (de aru) for formality. E.g., この水は有害です。(Kono mizu wa yūgai desu.) vs. その行為は社会的に有害である。(Sono kōi wa shakaiteki ni yūgai de aru.)
Negation of Na-Adjectives
To negate a na-adjective, you use ではありません (de wa arimasen) or ではない (de wa nai). E.g., この物質は有害ではありません。(Kono busshitsu wa yūgai de wa arimasen.) - This substance is not harmful.
Nominalization with 'koto' or 'no'
You can turn a sentence describing something as harmful into a noun phrase using こと (koto) or の (no). E.g., 有害であることは明らかだ。( Yūgai de aru koto wa akiraka da.) - The fact that it is harmful is clear.
Using 'to' with verbs like 'consider' or 'judge'
When stating that something is considered or judged to be harmful, you use 〜と〜される/みなされる. E.g., それは有害であると見なされている。(Sore wa yūgai de aru to mina sarete iru.) - It is considered to be harmful.
Examples by Level
これは有害な食べ物ですか？
Is this harmful food?
有害な (yūgai na) is used to describe the noun 食べ物 (tabemono).
煙は有害です。
Smoke is harmful.
有害です (yūgai desu) is a simple statement of fact.
有害な虫。
Harmful insect.
A noun phrase: 有害な (yūgai na) modifies 虫 (mushi).
水は有害ではありません。
The water is not harmful.
Negation using ではありません (de wa arimasen).
これは有害な場所ですか？
Is this a harmful place?
有害な (yūgai na) modifies 場所 (basho).
有害な音。
Harmful sound.
Noun phrase: 有害な (yūgai na) + noun.
有害な光。
Harmful light.
有害な (yūgai na) modifies 光 (hikari).
有害なガス。
Harmful gas.
有害な (yūgai na) modifies ガス (gasu).
この化学物質は有害なガスを発生させる。
This chemical substance generates harmful gases.
有害な (yūgai na) describes ガス (gasu).
喫煙は健康に有害です。
Smoking is harmful to health.
有害です (yūgai desu) is used predicatively.
有害な影響を避けるべきだ。
We should avoid harmful effects.
有害な (yūgai na) modifies 影響 (eikyō). べきだ (beki da) indicates obligation.
この食品添加物は有害かもしれません。
This food additive might be harmful.
かもしれません (kamoshiremasen) expresses possibility.
子供には有害なコンテンツ。
Harmful content for children.
有害な (yūgai na) modifies コンテンツ (kontentsu).
有害な電波。
Harmful radio waves.
有害な (yūgai na) modifies 電波 (denpa).
この薬は有害ですか？
Is this medicine harmful?
A direct question about the nature of the medicine.
有害な行為。
Harmful act.
有害な (yūgai na) modifies 行為 (kōi).
この地域では、有害な化学物質の流出が懸念されています。
There are concerns about the leakage of harmful chemical substances in this region.
有害な (yūgai na) modifies 化学物質 (kagakubusshitsu). 懸念されています (kenen sarete imasu) indicates a state of being concerned.
長時間の紫外線暴露は皮膚に有害であることが科学的に証明されています。
It has been scientifically proven that prolonged UV exposure is harmful to the skin.
有害であること (yūgai de aru koto) nominalizes the clause. 証明されています (shōmei sarete imasu) indicates it's proven.
ソーシャルメディアの過剰な利用は、若者の精神衛生に有害な影響を与える可能性があります。
Excessive use of social media may have harmful effects on the mental health of young people.
有害な (yūgai na) modifies 影響 (eikyō). 可能性があります (kanōsei ga arimasu) expresses possibility.
この製品には、子供にとって有害な成分が含まれていません。
This product does not contain ingredients that are harmful to children.
有害な (yūgai na) modifies 成分 (seibun). Negation with 〜ていません (te imasen).
未成年者への不適切な情報提供は、社会的に有害であると見なされています。
Providing inappropriate information to minors is considered socially harmful.
有害である (yūgai de aru) is used formally. 見なされています (mina sarete imasu) means 'is considered'.
有害な廃棄物の処理には特別な注意が必要です。
Special care is needed for the disposal of harmful waste.
有害な (yūgai na) modifies 廃棄物 (haikibutsu).
この地域の水質は、有害な汚染物質によって悪化しています。
The water quality in this region is deteriorating due to harmful pollutants.
有害な (yūgai na) modifies 汚染物質 (osenbusshitsu).
過剰な騒音は、健康に有害な影響を与える。
Excessive noise has harmful effects on health.
有害な (yūgai na) modifies 影響 (eikyō).
化学兵器の使用は、国際法により明確に禁止されており、極めて有害であると見なされています。
The use of chemical weapons is explicitly prohibited by international law and is considered extremely harmful.
有害である (yūgai de aru) is used in a formal statement. 見なされています (mina sarete imasu) indicates a widely accepted view.
現代社会における情報過多は、人々の認知能力に有害な影響を及ぼすという研究結果がある。
There are research findings suggesting that information overload in modern society has harmful effects on people's cognitive abilities.
有害な (yūgai na) modifies 影響 (eikyō). 〜という研究結果がある (to iu kenkyū kekka ga aru) introduces research findings.
環境汚染物質の中には、長期的に見ると人体に有害であるものが少なくない。
Among environmental pollutants, there are not a few that are harmful to the human body in the long term.
有害である (yūgai de aru) is used in a more formal context. 〜ものが少なくない (mono ga sukunai) means 'there are many'.
この種の広告は、特に未成年者の健全な発達に対して有害であると批判されています。
This type of advertising is criticized for being harmful, especially to the healthy development of minors.
有害である (yūgai de aru) is used. 〜と批判されています (to hihan sarete imasu) means 'is criticized as'.
遺伝子組み換え作物の安全性については、一部で有害である可能性が指摘されている。
Regarding the safety of genetically modified crops, the possibility of them being harmful has been pointed out by some.
有害である (yūgai de aru) is used. 〜可能性が指摘されている (kanōsei ga shiteki sarete iru) means 'the possibility has been pointed out'.
過剰なアルコール摂取は、肝臓に深刻な、そして回復不能な有害作用をもたらす。
Excessive alcohol intake brings about serious and irreversible harmful effects on the liver.
有害作用 (yūgai sayō) is a compound noun meaning 'harmful effect/action'.
テクノロジーの進歩は便利さをもたらす一方で、その濫用は社会に有害な結果を招きかねない。
While technological advancements bring convenience, their misuse can lead to harmful consequences for society.
有害な (yūgai na) modifies 結果 (kekka). 〜かねない (kanenai) expresses that something undesirable might happen.
環境保護の観点から、一部の産業活動は生態系に有害であると評価されている。
From an environmental protection perspective, some industrial activities are evaluated as being harmful to the ecosystem.
有害である (yūgai de aru) is used. 〜と評価されている (to hyōka sarete iru) means 'is evaluated as'.
現代のメディア環境における情報過多は、人々の精神的健康に長期的に有害な影響を及ぼす可能性を否定できない。
It cannot be denied that information overload in the modern media environment may have long-term harmful effects on people's mental health.
有害な (yūgai na) modifies 影響 (eikyō). 〜可能性を否定できない (kanōsei o hitei dekinai) expresses that the possibility cannot be denied.
特定の化学物質の慢性的な曝露は、生殖機能に深刻な、そしてしばしば回復不能な有害作用を引き起こすことが、疫学研究によって示唆されている。
Epidemiological studies suggest that chronic exposure to certain chemical substances can cause serious and often irreversible harmful effects on reproductive function.
有害作用 (yūgai sayō) is used. 〜によって示唆されている (ni yotte shisa sarete iru) means 'is suggested by'.
グローバリゼーションの進展は経済的利益をもたらす一方で、文化的多様性や地域社会の持続可能性に対して有害な側面も持ち合わせている。
While the advancement of globalization brings economic benefits, it also possesses harmful aspects towards cultural diversity and the sustainability of local communities.
有害な (yūgai na) modifies 側面 (sokumen).
非科学的な健康情報や誤った健康法は、一般市民の健康維持にとって有害無益であるばかりでなく、場合によっては生命を脅かす可能性すらある。
Unscientific health information and incorrect health practices are not only harmful and useless for the general public's health maintenance, but in some cases, they can even pose a threat to life.
有害無益 (yūgai mu’eki) is a compound meaning 'harmful and useless'. 〜ばかりでなく (bakari de naku) means 'not only'.
遺伝子編集技術の倫理的な問題点については、その潜在的な応用が未知の、そして制御不能な有害事象を引き起こすリスクが孕んでいるという懸念が表明されている。
Regarding the ethical issues of gene editing technology, concerns have been expressed that its potential applications harbor the risk of causing unknown and uncontrollable harmful events.
有害事象 (yūgai jijō) is a compound noun meaning 'harmful event/phenomenon'.
産業界における環境負荷の低減は、持続可能な社会の実現に向けた喫緊の課題であり、有害物質の排出抑制は最優先事項の一つである。
Reducing the environmental burden in industry is an urgent issue for the realization of a sustainable society, and the suppression of harmful substance emissions is one of the top priorities.
有害物質 (yūgai busshitsu) is a compound noun meaning 'harmful substances'.
デジタルデトックスの必要性が叫ばれる背景には、スマートフォンの過剰な使用がもたらす、精神的、社会的な有害作用への危機感がある。
Behind the call for the necessity of digital detox lies a sense of crisis regarding the mental and social harmful effects brought about by excessive smartphone use.
有害作用 (yūgai sayō) is used.
気候変動がもたらす複合的な影響は、食料安全保障から公衆衛生に至るまで、広範な領域にわたって有害な連鎖反応を引き起こす可能性がある。
The complex impacts of climate change have the potential to trigger a harmful chain reaction across a wide range of domains, from food security to public health.
有害な (yūgai na) modifies 連鎖反応 (rensahannō).
現代社会における情報過多は、単に認知的な負荷を増大させるだけでなく、人々の精神的健康に長期的に有害な影響を及ぼす可能性が、神経科学的観点からも示唆されている。
It is suggested from a neuroscientific perspective that information overload in modern society not only increases cognitive load but also may have long-term harmful effects on people's mental health.
有害な (yūgai na) modifies 影響 (eikyō). 〜観点からも示唆されている (kanten kara mo shisa sarete iru) means 'is suggested from the perspective of'.
化学物質の慢性的な低レベル曝露が、生殖機能、神経系、さらには内分泌系に及ぼす潜在的な、そしてしばしば微妙な有害作用については、未だ解明されていない側面が多い。
There are many aspects yet to be elucidated regarding the potential, and often subtle, harmful effects of chronic low-level exposure to chemical substances on reproductive function, the nervous system, and even the endocrine system.
有害作用 (yūgai sayō) is used. 〜については、未だ解明されていない側面が多い (ni tsuite wa, imada kaimei sarete inai sokumen ga ōi) indicates many aspects are still not understood.
グローバリゼーションの不可逆的な進展は、経済的恩恵を享受する一方で、各地域の固有の文化遺産や社会構造に対して、不可避的かつ有害な変容を強いる側面も否定できない。
While the irreversible advancement of globalization brings economic benefits, it cannot be denied that it also forces inevitable and harmful transformations upon the unique cultural heritage and social structures of each region.
有害な (yūgai na) modifies 変容 (hen’yō).
現代における情報伝達の速度と範囲の拡大は、真偽不明な情報や扇動的な言説が急速に拡散することを可能にし、公衆の健全な判断能力に対して極めて有害な影響を与えかねない。
The expansion of the speed and scope of information transmission in modern times enables the rapid spread of unverified information and inflammatory discourse, which can have extremely harmful effects on the public's sound judgment.
有害な (yūgai na) modifies 影響 (eikyō). 〜を与えかねない (o atae kanenai) expresses that undesirable consequences may occur.
遺伝子編集技術の応用は、疾患治療に革命をもたらす可能性を秘めている反面、その予期せぬ、あるいは意図せぬ変異が、生態系全体に予測不能な、そして広範な有害事象を引き起こすリスクは、慎重な検討を要する。
While gene editing technology holds the potential to revolutionize disease treatment, the risk that its unexpected or unintended mutations may cause unpredictable and widespread harmful events to the entire ecosystem requires careful consideration.
有害事象 (yūgai jijō) is used. 〜は、慎重な検討を要する (wa, shinchō na kentō o yōsuru) means 'requires careful consideration'.
持続可能な開発目標（SDGs）の達成に向けた国際社会の取り組みは、経済成長と環境保全の両立を目指しているが、その過程で生じうる、一部の地域や産業に対する有害な副次的影響についても、十分な配慮が求められる。
Efforts by the international community towards achieving the Sustainable Development Goals (SDGs) aim to balance economic growth and environmental conservation, but sufficient consideration is also required for the harmful side effects that may arise in the process, affecting certain regions and industries.
有害な (yūgai na) modifies 副次的影響 (fukuzai teki eikyō).
デジタル化の急速な進展は、利便性の向上に寄与する一方で、サイバーセキュリティのリスク増大や、個人情報漏洩といった、社会全体に有害な影響をもたらす潜在的脅威も増大させている。
While the rapid advancement of digitalization contributes to improved convenience, it also increases potential threats that can bring about harmful effects on society as a whole, such as increased cybersecurity risks and personal information leakage.
有害な (yūgai na) modifies 影響 (eikyō).
気候変動による海面上昇や異常気象の頻発化は、沿岸部のインフラ、農業、そして公衆衛生システムに対して、複合的かつ壊滅的な有害作用を引き起こす可能性が、最新の科学的予測によって示されている。
The latest scientific projections indicate that sea-level rise and increased frequency of extreme weather events due to climate change have the potential to cause complex and catastrophic harmful effects on coastal infrastructure, agriculture, and public health systems.
有害作用 (yūgai sayō) is used. 〜によって示されている (ni yotte shimesarete iru) means 'is indicated by'.
Common Collocations
Common Phrases
— It is harmful.
この食べ物は体に有害です。(Kono tabemono wa karada ni yūgai desu.) - This food is harmful to the body.
— Harmful things.
有害なものを避けるようにしましょう。(Yūgai na mono o sakeru yō ni shimashō.) - Let's try to avoid harmful things.
— Harmful effects/influence.
その薬は有害な影響を与える可能性がある。(Sono kusuri wa yūgai na eikyō o ataeru kanōsei ga aru.) - That medicine may have harmful effects.
— Harmful substances.
有害な物質に触れないでください。(Yūgai na busshitsu ni furenaide kudasai.) - Please do not touch harmful substances.
— To be harmful (formal).
その行為は社会的に有害である。(Sono kōi wa shakaiteki ni yūgai de aru.) - That act is socially harmful.
— Harmful food.
有害な食品の販売は禁止されています。(Yūgai na shokuhin no hanbai wa kinshi sarete imasu.) - The sale of harmful food is prohibited.
— Harmful chemical substances.
有害な化学物質の取り扱いには注意が必要です。(Yūgai na kagaku busshitsu no toriatsukai ni wa chūi ga hitsuyō desu.) - Care is needed when handling harmful chemical substances.
— Harmful radio waves/electromagnetic waves.
有害な電波を発する機器は規制されている。(Yūgai na denpa o hassuru kiki wa kisei sarete iru.) - Devices emitting harmful radio waves are regulated.
— Harmful insects.
有害な昆虫に刺されないように注意してください。(Yūgai na konchū ni sasararenai yō ni chūi shite kudasai.) - Please be careful not to be bitten by harmful insects.
— Harmful aspects.
その技術には有害な側面もある。(Sono gijutsu ni wa yūgai na sokumen mo aru.) - That technology also has harmful aspects.
Often Confused With
'Kiken' means dangerous and focuses on immediate risk. 'Yūgai' means harmful and focuses on the damaging effect, which can be immediate or long-term. Something can be dangerous without being directly harmful (e.g., a steep cliff), or harmful without being immediately dangerous (e.g., a slow-acting poison).
'Songai' is a noun meaning damage or loss, often financial. 'Yūgai' is an adjective describing the cause or quality of being harmful. You might say an action caused 'songai,' and that the action itself was 'yūgai'.
'Akueikyō' means negative influence or adverse effect, often used for psychological or social impacts. 'Yūgai' is broader and can include physical harm. 'Akueikyō' is a type of 'yūgai' effect.
Idioms & Expressions
— Harmful and useless; doing more harm than good.
この計画は有害無益だと多くの人が考えている。(Kono keikaku wa yūgai mu'eki da to ōku no hito ga kangaete iru.) - Many people think this plan is harmful and useless.
Formal— Pest control (literally 'harmful insect removal').
庭の害虫駆除を業者に依頼した。(Niwa no gaichū kujo o gyōsha ni irai shita.) - I asked a company to do pest control in the garden.
Neutral— Adverse event; harmful incident (often used in medical or scientific contexts).
臨床試験中にいくつかの有害事象が報告された。(Rinshō shiken-chū ni ikutsuka no yūgai jijō ga hōkoku sareta.) - Several adverse events were reported during the clinical trial.
Formal— Degree of harmfulness; toxicity level.
この物質の有害度は非常に高い。(Kono busshitsu no yūgaido wa hijō ni takai.) - The degree of harmfulness of this substance is very high.
Formal— Harmful microorganisms.
食品の安全のためには、有害微生物の繁殖を抑える必要がある。(Shokuhin no anzen no tame ni wa, yūgai biseibutsu no hanshoku o osaeru hitsuyō ga aru.) - For food safety, it is necessary to suppress the proliferation of harmful microorganisms.
Formal— Harmful books; banned literature (often used in censorship contexts).
有害図書として指定された本は図書館から撤去された。(Yūgai tosho to shite shitei sareta hon wa toshokan kara tekkyo sareta.) - Books designated as harmful literature were removed from the library.
Formal— Harmful industries (industries that cause significant environmental or social damage).
有害産業に対する規制を強化すべきだ。(Yūgai sangyō ni taisuru kisei o kyōka subeki da.) - Regulations on harmful industries should be strengthened.
Formal— Harmful information (e.g., misinformation, propaganda).
インターネット上には有害な情報も多く拡散している。(Intānetto-jō ni wa yūgai na jōhō mo ōku kakusan shite iru.) - Harmful information is also widely spread on the internet.
Neutral— Harmful social phenomena.
いじめは有害な社会現象の一つである。(Ijime wa yūgai na shakai genshō no hitotsu de aru. - Bullying is one of the harmful social phenomena.)
Formal— Harmful influence or effect.
過度なストレスは心身に有害な影響を与える。(Kado na sutoresu wa shinshin ni yūgai na eikyō o ataeru.) - Excessive stress has harmful effects on mind and body.
NeutralEasily Confused
Both words relate to negative outcomes and potential harm.
'Kiken' (dangerous) emphasizes the potential for immediate risk or injury. It's about the possibility of something bad happening. 'Yūgai' (harmful) emphasizes the actual damaging effect or consequence. Something can be 'kiken' without causing lasting damage (e.g., a loud noise), and something can be 'yūgai' without being immediately 'kiken' (e.g., a slow-acting toxin).
高い場所は<strong>危険</strong>ですが、この水は<strong>有害</strong>です。(Takai basho wa <strong class='text-violet-600 dark:text-violet-400'>kiken</strong> desu ga, kono mizu wa <strong class='text-violet-600 dark:text-violet-400'>yūgai</strong> desu.) - High places are dangerous, but this water is harmful.
Both words deal with negative outcomes and damage.
'Songai' (damage, loss) is a noun referring to the result of harm, often financial or material. 'Yūgai' (harmful) is an adjective describing the quality or cause of the harm. You would say an action caused 'songai,' and that the action was 'yūgai.'
その事故は大きな<strong>損害</strong>をもたらしたが、原因となった物質は<strong>有害</strong>だった。(Sono jiko wa ōkina <strong class='text-violet-600 dark:text-violet-400'>songai</strong> o motarashita ga, gen'in to natta busshitsu wa <strong class='text-violet-600 dark:text-violet-400'>yūgai</strong> datta.) - That accident caused great damage, and the substance that caused it was harmful.
Both describe negative influences or outcomes.
'Akueikyō' (negative influence/effect) is often used for more abstract or psychological harm, like the impact of media or habits. 'Yūgai' (harmful) is broader and can encompass physical damage, toxicity, or any detrimental effect. 'Akueikyō' is a specific type of 'yūgai' effect.
ソーシャルメディアは若者に<strong>悪影響</strong>を与えることがある。それは精神的に<strong>有害</strong>だからだ。(Sōsharu media wa wakamono ni <strong class='text-violet-600 dark:text-violet-400'>akueikyō</strong> o ataeru koto ga aru. Sore wa seishinteki ni <strong class='text-violet-600 dark:text-violet-400'>yūgai</strong> da kara da.) - Social media can have a negative influence on young people because it is mentally harmful.
Both describe something that is not good.
'Fukenzen' (unhealthy, unsound) describes conditions or lifestyles that are detrimental to well-being or stability, often in a less direct or physical way than 'yūgai.' A 'fukenzen' lifestyle might lead to 'yūgai' health problems. 'Yūgai' focuses on causing damage, while 'fukenzen' focuses on lacking health or soundness.
<strong>不健全</strong>な食生活は、様々な病気に<strong>有害な</strong>影響を与える。( <strong class='text-violet-600 dark:text-violet-400'>Fukenzen</strong> na shokuseikatsu wa, samazama na byōki ni <strong class='text-violet-600 dark:text-violet-400'>yūgai na</strong> eikyō o ataeru.) - An unhealthy diet has harmful effects on various illnesses.
It's the direct opposite, making it a point of contrast.
'Mukai' (harmless) means something does not cause damage or injury. 'Yūgai' (harmful) means it does cause damage or injury. They are direct antonyms.
この植物は<strong>無害</strong>ですが、あの植物は<strong>有害</strong>です。(Kono shokubutsu wa <strong class='text-violet-600 dark:text-violet-400'>mukai</strong> desu ga, ano shokubutsu wa <strong class='text-violet-600 dark:text-violet-400'>yūgai</strong> desu.) - This plant is harmless, but that plant is harmful.
Sentence Patterns
Noun + は + 有害です。
この煙は<strong>有害です</strong>。
有害な + Noun。
<strong>有害な</strong>ガスに注意。
Noun + は + Noun + に + 有害です。
砂糖の摂りすぎは健康に<strong>有害です</strong>。
Noun + は + 有害な + Noun + を + 引き起こす (hikiochosu).
その化学物質は環境に<strong>有害な影響を引き起こす</strong>可能性があります。
Clause + は + 有害である + と + 考えられている (kangaerarete iru).
過度なストレスは、心身に<strong>有害であると考えられています</strong>。
Noun + は + Noun + に + 有害な + Noun + を + もたらす (motarasu).
不適切な使用は、機器に<strong>有害な結果をもたらす</strong>ことがあります。
Clause + は + Noun + に + 有害な + Noun + を + 及ぼす (oyobosu) + 可能性が + 指摘されている (shiteki sarete iru).
情報過多は、若者の精神衛生に<strong>有害な影響を及ぼす可能性があると指摘されています</strong>。
Noun + は + Noun + に + 有害である (yūgai de aru) + と + 評価されている (hyōka sarete iru).
一部の産業活動は、生態系に<strong>有害であると評価されています</strong>。
Word Family
Nouns
Adjectives
Related
How to Use It
High (especially in contexts related to safety, health, and environment).
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Forgetting the 'na' particle.
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有害な物質 (yūgai na busshitsu)
As a na-adjective, 有害 (yūgai) requires the particle な (na) when it directly modifies a noun. Omitting it, like saying 有害物質, is grammatically incorrect.
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Using 有害 (yūgai) for minor inconveniences.
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その渋滞は迷惑だ。(Sono jūtai wa meiwaku da.)
有害 (yūgai) implies significant damage or danger. For minor issues like traffic jams, 迷惑 (meiwaku - troublesome) or 不便 (fuben - inconvenient) are more appropriate.
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Confusing 有害 (yūgai) with 危険 (kiken).
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この化学物質は<strong>有害</strong>ですが、その場所は<strong>危険</strong>です。(Kono kagakubusshitsu wa <strong class='text-violet-600 dark:text-violet-400'>yūgai</strong> desu ga, sono basho wa <strong class='text-violet-600 dark:text-violet-400'>kiken</strong> desu.)
'Yūgai' focuses on the damaging effect, while 'kiken' focuses on the risk or potential for immediate harm. A chemical can be 'yūgai' (harmful) even if it's not immediately 'kiken' (dangerous) to handle with care.
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Using 有害です (yūgai desu) in highly formal writing.
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その行為は社会的に有害であると判断された。(Sono kōi wa shakaiteki ni yūgai de aru to handan sareta.)
For formal documents, academic papers, or official statements, 有害である (yūgai de aru) is preferred over the more conversational 有害です (yūgai desu).
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Using 有害 (yūgai) when 損害 (songai) is more appropriate.
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その事件は経済に大きな<strong>損害</strong>をもたらした。(Sono jiken wa keizai ni ōkina <strong class='text-violet-600 dark:text-violet-400'>songai</strong> o motarashita.)
'Yūgai' is an adjective describing the cause of harm. 'Songai' is a noun referring to the result of harm (damage, loss), often financial. The adjective describes the quality, while the noun describes the outcome.
Tips
Na-Adjective Rule
Remember that 有害 (yūgai) is a na-adjective. When it directly precedes a noun, you must add the particle な (na) after it, like in 有害な物質 (yūgai na busshitsu). Forgetting this is a common mistake.
Avoid Overuse
Since 有害 (yūgai) implies significant harm, avoid using it for minor inconveniences or slight annoyances. This can make your Japanese sound unnatural or overly dramatic. Use it for genuine risks and damages.
Stress the Second Syllable
The stress in 有害 (yūgai) falls on the second syllable: yu-GAI. Practicing this rhythm will help you pronounce it more naturally.
Kanji Clue
The kanji 害 (gai) in 有害 (yūgai) literally means 'harm' or 'damage.' Recognizing this component can help you infer the meaning of the word even if you haven't memorized it perfectly.
Seriousness of Warnings
In Japan, warnings are taken seriously. When you see or hear 有害 (yūgai), it's usually a significant warning about potential danger or negative consequences. Treat it with the appropriate level of caution.
Distinguishing from 危険 (kiken)
Remember that 危険 (kiken) means 'dangerous' and focuses on risk, while 有害 (yūgai) means 'harmful' and focuses on the damaging effect. They are related but not interchangeable in all contexts.
Sentence Building
Try creating your own sentences using 有害 (yūgai) in different contexts – describing a substance, an action, or an environment. This active recall will solidify your understanding.
Meaning of 有 (yū)
The kanji 有 (yū) means 'to have' or 'to possess.' So, 有害 (yūgai) literally means 'to have harm,' emphasizing that the thing described inherently contains or causes harm.
Formal vs. Informal
While 有害です (yūgai desu) is common, 有害である (yūgai de aru) is preferred in formal writing and speech for a more academic or official tone.
Memorize It
Mnemonic
Think of 'You Guy!' as a warning. If someone shouts 'You Guy! Danger!', it's clearly about something harmful. The 'You' sounds a bit like 'Yū' and 'Guy' sounds like 'gai'. So, 'Yū-gai' = 'You Guy! Danger!'.
Visual Association
Imagine a big, red 'X' or a skull and crossbones symbol superimposed over something that looks dangerous, like a chemical bottle or a jagged hazard sign. The 'X' represents harm, and the symbol is 'Yūgai'.
Word Web
Challenge
Try to describe three everyday objects or situations as either 有害 (yūgai) or not 有害 (yūgai), explaining your reasoning. For example, 'My computer is not 有害, but a broken electrical wire is 有害.'
Word Origin
The word 有害 (yūgai) is composed of two kanji: 有 (yū) meaning 'to have,' 'to possess,' or 'there is,' and 害 (gai) meaning 'harm,' 'damage,' or 'injury.' Together, they literally mean 'having harm' or 'possessing harm,' which directly translates to 'harmful.'
Original meaning: The kanji 害 (gai) itself is very old and has consistently represented the concept of harm or damage. The addition of 有 (yū) makes it an adjective describing something that inherently contains or causes such harm.
Sino-Japanese (derived from Chinese characters)Cultural Context
The term 'yūgai' carries a serious tone. It should not be used lightly or for minor inconvenconveniences. When discussing potential harm, it's important to be accurate and avoid exaggeration.
In English-speaking cultures, 'harmful' is a direct equivalent. Warnings about 'harmful substances' or 'harmful effects' are common in safety labels, health advisories, and legal documents.
Practice in Real Life
Real-World Contexts
Safety warnings and public announcements
- 有害な物質に注意 (yūgai na busshitsu ni chūi)
- 有害なガス発生の恐れ (yūgai na gasu hassei no osore)
- 子供には有害です (kodomo ni wa yūgai desu)
Product labeling and consumer information
- 有害な成分が含まれています (yūgai na seibun ga fukumarete imasu)
- 有害な使用方法 (yūgai na shiyō hōhō)
- 無害ですが、有害なものもあります (mukai desu ga, yūgai na mono mo arimasu)
Health and environmental discussions
- 健康に有害な影響 (kenkō ni yūgai na eikyō)
- 環境に有害な物質 (kankyō ni yūgai na busshitsu)
- 有害な汚染物質 (yūgai na osen busshitsu)
Academic and scientific reports
- 有害であると証明された (yūgai de aru to shōmei sareta)
- 有害な作用が確認された (yūgai na sayō ga kakunin sareta)
- 有害性についての研究 (yūgai sei ni tsuite no kenkyū)
Legal and regulatory contexts
- 有害物質の規制 (yūgai busshitsu no kisei)
- 有害行為の禁止 (yūgai kōi no kinshi)
- 有害な結果を招く (yūgai na kekka o maneku)
Conversation Starters
"Have you ever seen a warning sign with 有害 (yūgai) on it? What was it warning about?"
"What kind of things do you think are 有害 (yūgai) in our daily lives?"
"Can you think of a time when something was described as 有害 (yūgai) in the news or a documentary?"
"How does the word 有害 (yūgai) make you feel when you see or hear it?"
"Are there any everyday items that might be considered 有害 (yūgai) if used improperly?"
Journal Prompts
Write about a time you encountered something that was clearly 有害 (yūgai) and how you reacted or what precautions you took.
Imagine you are writing a public safety announcement. Use the word 有害 (yūgai) to describe a potential danger in your community.
Reflect on the difference between something that is merely inconvenient and something that is truly 有害 (yūgai). Provide examples.
Consider the potential 有害 (yūgai) effects of modern technology on society. Write a short paragraph discussing this.
Describe a situation where something was thought to be 有害 (yūgai) but was later found to be harmless, or vice versa.
Frequently Asked Questions
10 questions'Yūgai' means harmful, focusing on the damaging effect. 'Kiken' means dangerous, focusing on the potential for immediate risk or injury. Something can be 'kiken' without causing lasting harm, and something can be 'yūgai' without being immediately 'kiken'. For example, a steep cliff is 'kiken', but a slow-acting poison is 'yūgai'.
Yes, while it often refers to physical harm, 'yūgai' can also describe psychological, social, or environmental damage. For instance, excessive exposure to certain media might be considered 'yūgai' for children's development.
As a na-adjective, it's often used as 'yūgai na + noun' (e.g., 有害な物質 - harmful substance) or predicatively as 'yūgai desu' (polite) or 'yūgai de aru' (formal) (e.g., この水は有害です - This water is harmful).
'Yūgai' is generally considered neutral to formal. It's common in warnings, official notices, and serious discussions. While it can be used in spoken Japanese, it might sound overly strong or dramatic in very casual conversations unless the topic truly warrants it.
You'll frequently encounter 'yūgai' in safety warnings, product labels (especially for chemicals or medicines), environmental reports, public health announcements, and scientific or academic texts discussing negative impacts.
The direct opposite is 無害 (mukai), meaning harmless. Other related antonyms include 有益 (yūeki) meaning beneficial, and 安全 (anzen) meaning safe.
No, 'yūgai' implies a significant negative impact, damage, or danger. For minor annoyances, words like 迷惑 (meiwaku - troublesome) or 不便 (fuben - inconvenient) are more appropriate.
The kanji 害 (gai) means 'harm,' 'damage,' or 'injury.' It's a strong symbol often associated with danger and the need for caution, appearing in words like 災害 (saigai - disaster) and 障害 (shōgai - obstacle, disability).
'Yūgai' is an adjective meaning 'harmful,' describing a cause or quality. 'Songai' is a noun meaning 'damage' or 'loss,' referring to the result of harm, often financial. You might say an action was 'yūgai' and it caused 'songai'.
Yes, it's very common in fields related to public safety, health and medicine, environmental science, consumer product safety, and law/regulation, where the potential for harm needs to be clearly communicated.
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Summary
有害 (yūgai) is an adjective meaning 'harmful' or 'damaging.' It's used to describe things that can cause injury, negative effects, or detriment, often appearing in warnings, safety instructions, and discussions about health and the environment. Think of it as a strong word for something that is bad for you or others.
- Harmful; causing damage or injury.
- Used for dangerous substances, actions, or environments.
- Often seen in warnings and safety information.
- Implies a significant negative impact.
Na-Adjective Rule
Remember that 有害 (yūgai) is a na-adjective. When it directly precedes a noun, you must add the particle な (na) after it, like in 有害な物質 (yūgai na busshitsu). Forgetting this is a common mistake.
Context is Key
While 有害 (yūgai) means harmful, the specific type of harm (physical, chemical, social, etc.) will depend on the context. Pay attention to the surrounding words and the situation to understand the full meaning.
Avoid Overuse
Since 有害 (yūgai) implies significant harm, avoid using it for minor inconveniences or slight annoyances. This can make your Japanese sound unnatural or overly dramatic. Use it for genuine risks and damages.
Stress the Second Syllable
The stress in 有害 (yūgai) falls on the second syllable: yu-GAI. Practicing this rhythm will help you pronounce it more naturally.
Example
有害な化学物質は環境に悪影響を与える。
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This Word in Other Languages
More health words
しばらく
B1For a while, for some time.
異変がある
B1To have an unusual change or abnormality.
異常な
B1Abnormal; unusual; irregular.
擦り傷
B1Scratch, graze, abrasion.
吸収する
B1To absorb.
禁酒
B1Abstinence from alcohol; the act of refraining from alcohol.
痛む
A2to hurt; to ache
鍼灸
B1Acupuncture and moxibustion; traditional Chinese medicine treatments.
急性的
B1Acute.
急性な
B1Acute
