YABAI

YABAI is a Japanese slang dictionary that gathers 308 real slang, internet, fandom and everyday words and gives each one a card built around giant Japanese typography. The site frames the project simply: やばい, 推し, 草, エモい — what they mean, how they sound, and who you can actually say them to. Every entry is treated as more than a translation lookup. Each word carries a meaning, an original example sentence, a vibe check that signals whether it is safe to use, friends only or something to be careful with, a culture note where there is something worth knowing, and a short story about where the word came from and who says it now. The result is a reference that answers the two questions a plain dictionary leaves open: how does this word actually sound in use, and can I say it? The 308 words can be read on the website, browsed alphabetically or by category, or carried in the Android app, which the site describes as putting all of them in your pocket. The gap YABAI is built to fill is the one left by formal language study. Textbooks teach Japanese that stops at the classroom door, and YABAI presents itself as the other half — the slang, internet, fandom and everyday vocabulary that lives outside a syllabus. Words like 草, described as 'lol, literally grass', or 推し or タイパ rarely come with the context a learner needs in order to use them without embarrassment: how casual is this, is it regional, is it tied to a particular subculture, is it something a visitor should avoid? A literal translation can be found almost anywhere, but a translation does not tell you whether a word is safe with a stranger, a colleague or only among friends. It also does not tell you the story, which is often the part that makes a word memorable. YABAI treats those missing layers — tone, social risk, cultural placement and origin — as the content, not as footnotes. The first of the five elements on every card is the meaning. Each word opens with one punchy line that captures its essence; やばい, for instance, is summed up as 'Amazing. Terrible. Insane.' — a deliberately informal line that mirrors how fluid the word is. That is followed by the full sense written in plain English, so a reader who wants precision is not left with a slogan. The second element is the example: an original Japanese sentence with a translation, showing the word at work rather than in isolation. The site is explicit that these sentences are never a quote and never a brand, which means the examples are written for the dictionary itself instead of being lifted from advertising or celebrity speech. For a learner, that distinction matters, because example sentences drawn from real but arbitrary sources can smuggle in formality levels or promotional tone that do not represent everyday use. The third element is the vibe check, and the site calls it out as the one thing dictionaries never give you. Each word is labelled Safe to use, Friends only, or Be careful, and is accompanied by tone hints such as self-deprecating, internet, or Kansai dialect. This is practical social information: it is the difference between a word a visitor can drop casually and one that will sound off, dated or too familiar in the wrong company. The fourth element is the culture note, which places the word in Japanese life — included when there is something worth knowing. Together, the vibe badge and the culture note turn a definition into a kind of usage briefing, so the reader learns not only what a word means but where it sits and who tends to say it. For anyone who has learned a word from a subtitle and then hesitated to use it, this is the layer that resolves the hesitation. The fifth element is the story: a short read on where the word came from and who says it now. The site takes an unusually honest stance here, stating that when an origin is genuinely disputed, the card says so instead of picking one version. In a space where slang etymologies are frequently repeated with false confidence online, admitting uncertainty is itself a feature — it tells readers which explanations are settled and which are guesses. All five elements are presented on cards designed to be looked at rather than merely consulted, with the headword set in giant Japanese typography alongside its romaji, its meaning, its example sentence and its vibe badge. The site's own phrasing for this is that each word is not a dictionary entry but a card you want to look at, reflecting a design choice to make browsing pleasant and screenshot-friendly rather than austere. A sample card shows やばい in large type with its romaji, meaning, example and vibe badge together. Structurally, the content is organized in two ways. Readers can browse all 308 words as an A–Z list, or move through the eight categories that describe where you hear each word: Slang with 72 entries, Internet with 58, Otaku with 46, Everyday with 44, Untranslatable with 30, Reactions with 26, Cute with 24, and Anime-ish with 8. The homepage introduces the collection with eight starter words, one from each category — やばい, 推し, 草, エモい, それな, もふもふ, タイパ and ツンデレ — each shown with a short gloss and a category tag. The app itself is designed for low-commitment use: the dictionary ships inside the app in 13 languages, works offline, and every word can be read aloud by your device. The site states that nothing you collect leaves your phone. There are no streaks, no tests, no levels and no guilt; the experience is described as a Japanese culture snack — open it for a minute, meet one word, close it. The site also hosts short video content, including a thirty-second explanation of やばい, and notes that there are more videos on the yabai page and on seven other word pages. The benefits follow directly from that structure. A learner gets the meaning quickly, then gets the surrounding context that makes the word usable: an example to model, a vibe badge to judge risk, a culture note to understand placement, and a story to remember it by. Because the origins of disputed words are labelled as disputed, readers are not handed confident misinformation. Because the dictionary ships offline in 13 languages and can read words aloud, it works without a signal and supports pronunciation and listening as well as reading. Because there are no streaks, tests or levels, there is no backlog to feel guilty about — the dictionary can be used in the small gaps of a day. And because it is a paid app with no ads, no sign-up and no subscription, the experience stays uninterrupted by advertising or account prompts, with nothing collected leaving the phone. Concretely, the dictionary fits several kinds of sessions. Someone who has just heard やばい in an anime or a video can look it up, read the one-line meaning, then check the vibe badge before deciding whether to try it with a Japanese friend. A fan of anime or otaku culture running into 推し or ツンデレ can browse the Otaku or Anime-ish category and find the term with its example and story attached. A reader curious about concepts that resist direct translation can explore the Untranslatable set of 30 words, such as エモい, described on the site as beautiful in a way that aches. An internet user puzzled by 草 can go straight to the Internet category, which holds 58 entries. Someone with a spare minute can open the app for a single card rather than a study session. Someone offline — on a flight, underground, or without data — still has the full dictionary available, and can have the device read a word aloud. And someone who prefers listening can start with the short videos, such as the thirty-second piece on how one Japanese word means both 'Amazing!' and 'Oh no'. The obvious audience is people learning Japanese who have moved past the beginner material and want the vocabulary that textbooks leave out, along with anyone who consumes Japanese media, anime, fandom or internet content and wants to understand what people are actually saying. It suits readers who care about appropriateness as much as definition, and who like the story and culture behind a word rather than only its translation. The app is available as a paid Android download on Google Play, with the website serving the full word list for reading in a browser; the site notes it is a paid app with no ads, no sign-up and no subscription. The project was built end to end with AI agents in Claude Code, according to its Product Hunt description, and it is published under the YABAI name with 'yabai' as its site and product slug. Its listed topics are Android, Education and Languages. Taken as a whole, YABAI's value proposition is context. It takes 308 Japanese slang, internet, fandom and everyday words and wraps each one in the meaning, example, vibe check, culture note and story that a plain translation omits — and it says so honestly when an origin is disputed. Read on the web or carried offline in the Android app across 13 languages, with read-aloud support and no streaks, tests or ads, it is a dictionary built for a minute at a time that still tells you exactly who you can say each word to.