22 Japanese ways to say “That’s dangerous”

When you want to warn someone in Japanese that something’s risky or unsafe, there are lots of ways to say it. Whether you’re chatting casually with friends or need a polite phrase for a serious situation, Japanese has you covered.

Learning these expressions can add color and accuracy to your conversations. Plus, it helps you sound more natural and confident when speaking.

This guide shares 22 different ways to say “That’s dangerous” in Japanese, from casual slang to formal warnings.

We’ll break them down with pronunciation tips and little explanations, so you can pick the right phrase for any moment.

Each phrase comes with a simple breakdown to help you remember and use it easily.

Ready to keep your conversations safe and sharp? Let’s dive in!

Understanding Danger in Japanese

Before jumping into the phrases, it’s good to know how the concept of “danger” works in Japanese. The word 危険 (きけん, kiken) means “danger” and shows up in many phrases.

From there, you’ll find casual ways and formal warnings built around this core idea.

Japanese also has plenty of expressions that convey “watch out” or “be careful” which are handy to know.

If you want a solid foundation, a beginner phrasebook can be a perfect companion.

With that in mind, let’s explore some common ways to say “That’s dangerous” that you can start using today.

Keep practicing and you’ll feel more confident spotting and pointing out hazards in Japanese.

Part 1: Casual Suggestions

1. 危ない！ (Abunai!) – “Dangerous!”

“Abunai” is the most common, straightforward way to say “That’s dangerous!” in casual speech.

It literally means “dangerous” or “watch out,” and you can shout it quickly when you spot danger.

It’s used in everyday situations like warning someone about a slippery floor or a moving vehicle.

Because it’s short and sharp, it’s perfect for urgent warnings.

Note: You can add “よ！” (yo!) at the end for emphasis: 危ないよ！(Abunai yo!)

Once you get comfortable with “Abunai,” you’ll notice it everywhere in anime, dramas, and conversations.

2. 気をつけて！ (Ki o tsukete!) – “Be careful!”

This phrase literally means “Pay attention” or “Take care.”

It’s a softer, more polite way to warn someone about danger without sounding too alarming.

Great for everyday use when you want to remind friends or family to watch out.

“Ki” means “spirit” or “mind,” and “tsukete” means “attach” or “pay.”

Try saying it with a gentle tone to sound caring, not bossy.

It’s a versatile phrase that pairs well with other warnings you’ll learn below.

3. 危険だよ (Kiken da yo) – “It’s dangerous.”

Adding “だよ” (da yo) at the end of 危険 (kiken) makes the phrase more conversational and casual.

“Kiken” means “danger,” and “da yo” is a sentence ending that softens the statement.

This phrase is great for calmly telling someone something is dangerous.

Use it when the danger isn’t urgent but still important to notice.

It works well in conversations where you want to sound clear but not frightening.

Once you say this, your friends will know you’re looking out for them.

4. やばい！ (Yabai!) – “Dangerous!” / “Oh no!”

“Yabai” is a slang term that can mean “dangerous,” “terrible,” or “awesome,” depending on context.

Young people use it a lot to express surprise or alarm.

When used to mean “dangerous,” it’s like saying “Oh no, that’s bad!”

Because it’s informal and slangy, avoid using it in formal situations.

It’s a fun and expressive way to react quickly to danger.

Be careful with tone — it can sound playful or serious depending on how you say it.

5. 気をつけろ！ (Ki o tsukero!) – “Watch out!” (rough)

This is a stronger, more commanding form of “be careful.”

“Tsukero” is the imperative (command) form of “tsukeru.”

It’s common among close friends or in urgent situations where you need immediate attention.

Use it with caution — it can sound rude if used with strangers.

Great for high-energy moments where you want to warn loudly and clearly.

Try pairing it with a serious face to get the message across.

6. それは危ないよ (Sore wa abunai yo) – “That’s dangerous, you know.”

This phrase adds “それは” (sore wa), meaning “that is,” to “abunai.”

Adding “よ” (yo) makes it more conversational and caring.

It’s a gentle way to tell someone what they’re doing or about to do is dangerous.

Use it when you want to sound friendly but serious.

It’s perfect for casual conversations with friends or family.

It helps you sound natural and concerned without sounding bossy.

7. 危なすぎる！ (Abuna sugiru!) – “Too dangerous!”

“Sugiru” means “too much” or “excessive,” so adding it to “abunai” emphasizes the danger.

It’s like saying “That’s way too dangerous!”

This phrase adds drama and urgency to your warning.

Use it when something is clearly risky beyond normal.

It’s great for reactions in lively conversations or storytelling.

Practice this to sound more expressive and native-like.

8. 危険すぎる！ (Kiken sugiru!) – “Too dangerous!”

Similar to the previous phrase, but using “kiken” instead of “abunai.”

It sounds a bit more formal and serious.

Use this when you want to emphasize a serious risk.

It works well in conversations about health, safety, or accidents.

By combining “kiken” with “sugiru,” you show strong concern.

Keep this one handy for important warnings.

Part 2: Polite & Formal Suggestions

9. 危険です (Kiken desu) – “It is dangerous.”

This is the polite form of “It’s dangerous.”

“Desu” makes “kiken” appropriate for formal or business settings.

Use this when talking to people you don’t know well or in official situations.

It’s clear and respectful, perfect for safety announcements.

You’ll often hear this in workplaces or public places.

It’s a great phrase to keep in your polite conversation toolkit.

10. 危険だと思います (Kiken da to omoimasu) – “I think it’s dangerous.”

This phrase is a polite way to express your opinion about danger.

“Omoimasu” means “I think,” softening the statement.

It’s useful when you want to be polite but still warn someone.

Great for meetings or conversations with superiors.

You can use it to gently suggest caution.

It’s a respectful way to share your concern without sounding pushy.

11. ご注意ください (Go-chūi kudasai) – “Please be careful.”

This phrase is a formal, respectful way to tell someone to be careful.

“Go” is an honorific prefix, “chūi” means “caution,” and “kudasai” is “please.”

It’s often used in signs or announcements.

Perfect for polite warnings in shops, offices, or public areas.

Using this phrase shows attention to manners and respect.

It’s a must-know for formal environments.

12. 危険が伴います (Kiken ga tomonai masu) – “Danger is involved.”

This phrase is a formal way to say “Danger is involved.”

“Tomonau” means “to accompany” or “to involve.”

It’s used in safety instructions or technical contexts.

Great for presentations or written warnings.

It sounds serious and precise.

Learning this adds polish to your formal Japanese vocabulary.

13. 危険な状況です (Kiken na jōkyō desu) – “It’s a dangerous situation.”

This phrase describes a situation as dangerous politely.

“Jōkyō” means “situation” or “condition.”

It’s common in news reports or official conversations.

Using this phrase shows you’re aware and serious about the danger.

It’s a useful phrase for discussing events or emergencies.

Practice it to sound more professional when needed.

14. 危険性があります (Kikensei ga arimasu) – “There is a risk/danger.”

“Kikensei” means “dangerousness” or “risk.”

“Arimasu” means “there is.”

This phrase is used to indicate the presence of danger or risk.

It’s common in formal reports, health warnings, or technical documents.

Useful for explaining hazards clearly and politely.

Learning this will help you sound knowledgeable and professional.

15. 危険を避けてください (Kiken o sakete kudasai) – “Please avoid danger.”

This polite phrase asks someone to avoid danger.

“Sakeru” means “to avoid,” and “kudasai” adds politeness.

Good for instructions or polite requests.

Use it when advising people to stay safe without being forceful.

It’s practical for guides, teachers, or caretakers.

Try using it to sound considerate and helpful.

16. 危険が予測されます (Kiken ga yosoku saremasu) – “Danger is predicted.”

This formal phrase is used for warnings about expected dangers.

“Yosoku” means “prediction” or “forecast.”

Common in weather reports or safety announcements.

It’s a precise, polite way to alert about potential risks.

Great for learning if you want to describe future dangers.

Helps you sound informed and professional.

Part 3: Very Casual / Native-like Expressions

17. マジ危ない！ (Maji abunai!) – “Seriously dangerous!”

“Maji” means “seriously” or “really.”

Adding it to “abunai” makes your warning sound urgent and emphatic.

This phrase is super casual and popular among youth.

Use it with close friends for a natural, emotional reaction.

It’s great for showing you’re really worried about the danger.

Be aware it’s informal and not for formal use.

18. ヤバすぎ！ (Yaba sugi!) – “Too dangerous!” (slang)

“Yaba” is a slang shortened form of “yabai,” and “sugi” means “too much.”

It’s used to say something is excessively dangerous or intense.

This phrase is playful and often used among young people.

It’s great for casual conversations and social media.

Watch your tone so it doesn’t sound like you’re joking when it’s serious.

Use it to sound hip and in touch with native speakers.

19. ちょっと危ないかも (Chotto abunai kamo) – “Maybe a little dangerous.”

This phrase adds “chotto” meaning “a little” and “kamo” meaning “maybe.”

It’s a softer way to express concern about danger.

Perfect for delicate situations or when you’re unsure.

It sounds natural and relatable in everyday talk.

Use it to gently warn without sounding too serious.

This nuance can help keep conversations light yet cautious.

20. ほんとに危ないよ (Hontoni abunai yo) – “Really dangerous, you know.”

“Hontoni” means “really” or “truly.”

Adding it to “abunai yo” emphasizes the seriousness of the danger.

It’s a natural phrase used among friends or family.

It shows genuine concern without sounding harsh.

Try using it when you want to be clear and sincere.

It’s a phrase that native speakers often use to stress warnings.

21. それ、危ないんじゃない？ (Sore, abunai n janai?) – “Isn’t that dangerous?”

This is a conversational way to ask if something might be dangerous.

“N janai?” softens the question and invites agreement or discussion.

It’s great for checking with friends about risky choices.

It sounds natural and friendly.

Use it to show care while opening a conversation.

This phrase helps you sound like a fluent, thoughtful speaker.

22. やめたほうがいいよ、危ないから (Yameta hō ga ii yo, abunai kara) – “You better stop, because it’s dangerous.”

This phrase combines advice and warning.

“Yameta hō ga ii” means “You better stop,” and “abunai kara” means “because it’s dangerous.”

It’s casual but caring advice to avoid danger.

Great for friends or family when you want to be persuasive yet kind.

It’s a practical phrase for real-life situations.

Use it to sound considerate and convincing.

Concluding Thought

Learning how to say “That’s dangerous” in so many Japanese ways gives you flexibility and confidence to communicate safety in any situation.

From casual slang to polite warnings, these phrases help you sound natural and thoughtful.

Keep practicing them in context, and you’ll be ready to protect yourself and others while sounding like a native!