What Does the Term “Yabai,” as Used by Japanese Young People, Mean?

If you’re a learner of Japanese, I assume you’ve heard of the word “yabai.” We’ll explore how it’s actually used by young people today.

I’m in charge of private lessons at TCJ, as well as teaching Japanese to foreign high school students at a Tokyo Metropolitan High School. In my interactions with both foreign and Japanese students, I often hear youth slang. Here are some examples of their conversations that I have actually heard.

Student A:「このダンスやばくない？むずっ」(Kono dansu yabakunai? Muzu.)
-Isn’t this dance crazy? It looks difficult.
Student B: 「うわっ。やばっ。こっちの動画もやばいよ？みてみて」(Uwa, yaba. Kocchi no douga mo yabaiyo. Mitemite.)
-Wow, that’s crazy. This video over here is also awesome. Check it out.
Student A:「やばやば。これはプロっしょ。あ！チャイムなった」(Yabayaba, kore ha puro ssho. a! chaimu natta.)
-This is really insane; it looks professional! Oh! The bell just rang.
Student B: 「やばい！遅れる〜」(Yabai! okureru-)
–Oh no! We’re going to be late!

Student C:「数学のテスト、やばかった。まじオワタ」(Suugaku no tesuto, yabakatta. Maji owata.)
-The math test went horribly. I totally bombed it.
Student D:「また赤点かよ。このままじゃやばいっしょ。勉強しろよ」(Mata akaten kayo. Konomama ja yabaissho. Benkyou shiroyo.)
-Are you failing again? This can’t happen again. You’d better study harder.
Student C:「てか、天気やばくね？」(Teka, tenki yabakune?)
-By the way, doesn’t the weather look crazy?
Student D:「やべー。傘持ってきてねー」(Yabe. Kasa mottekitene-.)
–Oh no! I didn’t bring an umbrella!

Student A:「見てみて。このダンス動画、最高だよ！Bさんもそう思わない？難しいダンスだね。踊れるのすごいなー」
– Look at this dance video! It’s amazing! Don’t you think so? The dance looks difficult. It’s so impressive that they can dance like that.
Student B:「本当だ！最高！こっちのダンス動画もとてもかっこいいよ。見て見て」
-You’re right! It’s incredible! This dance video is cool too. Have a look!
Student A:「すごいすごい！こんなキレキレのダンスが踊れるなんて、これはプロのダンサーだよ。あ！チャイムがなったよ。教室に行こう！」
-Wow, wow! I can’t believe they can dance with such technique! They are professionals! Ah! The bell rang! Let’s go to our classroom!
Student B:「もう休み時間終わり？授業に遅れるかも。遅れたら最悪！」
-Is the break already over? We might be late for class, which could be the worst!

Student C:「数学のテスト、点数が最悪だった。俺の人生、終わった」
-My result for the math test was horrible. My life is over.
Student D:「また赤点かよ。このまま赤点ばかりだと進級があぶないよ。勉強しろよ」
-Are you failing again? If you keep getting a failing grade, you won’t be able to move up to the next grade. You’d better study harder.
Student C:「テストの話はもういいよ。そんなことより、天気が悪くなってきた。雨が降りそうだと思わない？」
-Let’s not talk about that anymore. By the way, the weather is getting worse. Don’t you think it’s going to rain?
Student D:「最悪だ。傘を持ってこなかった」
-That’s unfortunate, I didn’t bring an umbrella!

As you can see, a variety of words across a wide range of meanings are replaced with “yabai.” Surprisingly, they even use it as an exclamation when they are shocked, using forms like “yaba” or “yabe.”

The word “yaba,” derived from “yabai,” has existed since the Edo period and originally referred to something dangerous or an unfavorable situation.
Note: The term “yabai” is believed to have existed in the Edo period, as evidenced by a passage in “Tōkaidūchū Hizakurige,” a humorous book published in 1802 by Jippensha Ikku, which states, “Odorera, yabana koto tarakikusaruna” (＝You all, don’t do anything dangerous).

There are various theories about how “yaba” evolved into the adjective form “yabai.” During the Meiji period, law enforcement officers (now known as police officers) referred to thieves as “yaba,” and they would often exclaim “yabai” (meaning they were in danger or in an unfavorable situation) when pursuing suspects vigorously. Meanwhile, at shooting ranges where illegal activities took place, “yaba” was used, and the term became associated with danger.
This usage continued after World War II, spreading as slang among criminals and delinquents in the underworld. For example, one might say, “I’m about to get arrested by the police” (indicating danger) or “This could lead to unfavorable results” (referring to an unfavorable situation).
In the Heisei period, the term started to trend negatively, meaning “not cool.” Gradually, it began to be used positively, with evaluations, such as “the actor is yabai” (meaning “cool” or “talented”) or “the TV show is yabai” (meaning “interesting”).

I personally, as someone who is no longer part of the younger generation, try to avoid using the term “yabai.” However, it sometimes slips out of my mouth when I’m impressed by something. Friends in their 30s and 40s use it too. As for those in their 50s and 60s, it seems to depend on the individual; I would say that those who have kids or interact with children might use it. I have never heard elderly people using the term. Nowadays, the influence of YouTube has grown significantly; I’ve even heard young children say, “Hikakin is yabai,” referring to the popular Japanese male YouTuber.

It goes without saying that the situations where you can use the word are limited to when you’re speaking with someone close to you. In formal situations where you’re required to use “keigo”—such as at a part-time job, during a job interview, in business settings, or when talking to elders or someone in a higher position—it is not appropriate to use “yabai.” When someone uses “yabai,” you may not know exactly what they mean by it. Additionally, some people might think, “You’re still acting like a student,” “You’re not serious enough,” or “You’re being disrespectful,” which could create a negative impression of you. Therefore, I would be careful and communicate thoughtfully, choosing appropriate words for each situation.

If you’re a Japanese learner, it’s up to you whether to use youth slang like “yabai” or other expressions you’ve recently learned from anime. Japanese has a wider vocabulary compared to other languages. While it might seem convenient to use “yabai” for everything, it would be even better to expand your vocabulary. Let’s build more vocabulary for casual conversations in our classes!

References
『悩ましい国語辞典』 (Troublesome National Language Dictionary) by Akira Kaminaga, Kadokawa Sophia Bunko (2019)
『新明解 国語辞典 第五版』 (Shin Meikai National Language Dictionary, 5th Edition) by Kyōsuke Kanedaichi, Sanseido (2003)
『日本俗語大辞典』 (Japanese Colloquial Dictionary) by Akihiko Yonekawa, Tōkyōdō Publishing (2003)
『日本国語大辞典 第2版』 (National Language Dictionary of Japan, 2nd Edition) by Yasuo Kitahara, Shogakukan (2003)
『若者言葉の研究 SNS時代の言語変化』 (A Study of Youth Language: Linguistic Changes in the SNS Era) by Yoshiho Horio, Kyushu University Press (2022)
Reference URL
Reference Cooperation Database
https://crd.ndl.go.jp/reference/detail?page=ref_view&id=1000329199