Japanese Streetslang (2020)

It's easy to create Japanese slang. Use a lot of "sound effect" words (I was walking down the alley and Bwa! the place blew up.), and onomatopoeia or mimesis; such as Baribari (sound of an engine; used when things are running smoothly") Ka-ching (sound of handcuffs, "be arrested") or Bokoboko (sound of hitting something hard, used when beating someone up).

Abbreviation is also a good way to make slang. Japanese tend to take one to three letters in a word, maybe combine it with a couple letters of another word, and use that; such as Sukebo (skateboard), pasokon (personal computer), and rimokom (remote control). Also, you can take the first letter of an English word, or the English spelling of a Japanese word, and use that, like H ('wanna H? Wanna fool around?).

Slang and Vocab

 * Aho/Do-aho (Osaka): Idiot/Big idiot.
 * Akan (Osaka): Bad, No Good, wrecked.
 * Anime: Hand drawn animation from Japan.
 * Baka/O-baka: Fool/Super-Fool
 * Cho: Super
 * Choo-bo: Junior High School Student.
 * Dachi/Dachi-ko: friend. choombatta
 * Deka: Detective
 * Dojin-shi: Fanzine, underground blackbook.
 * Etchi: Pervert, Have sex.
 * Gaki: Kid, Juves.
 * Ge-sen: Game Center
 * Hamaru: Play a game or braindance fanatically, immobilized, computer crash.
 * Hameru: Attack an enemy's weak points.
 * Hamewaza: Shut out enemy's attacks, Unfair fighting style
 * Hen na: Strange
 * Idol: Young (12 - 20) Corporate entertainer.
 * Imbeda: Very old game, Sucker, Sitting duck.
 * Keto: Foreigner, White (Chambara).
 * Kubi: Get fired from a corp.
 * Kuso-Ge: Shitty Game, boring/awful game.
 * Kuso: Shit.
 * Muzu/Muzui: Difficult (short for "muzukashii")
 * Manga: are comics or graphic novels created in Japan or using the Japanese language and conforming to a style developed in Japan in the late 19th century.
 * Mabu-dachi: Best friend.
 * Nan-A: South Africa
 * Nambei: South America
 * Namban/Namban-jin: Euro or Yank
 * Nikkei-jin: Japanese-related foreigners.
 * OL: Office Lady, a female corporate.
 * Omawari: Police.
 * Onna-gata/Okama: Female impersonators.
 * Otaku: Maniac, A fanatic to their hobby, has a deep understanding of anime, manga, or video games.
 * Pampee: Common people, Non-edgerunners, Beavers
 * Pu/Pu-taro: Unemployed, Living off the 'rents.
 * Ronin: Student who failed entrance exams, out of work.
 * Salaryman: Corp.
 * Satsu: Police, Cops.
 * Sessya: I, Me, Myself.
 * Shimeru!: Kill!, Hold on!
 * Tame: Waiting for a chance to attack.
 * Tansha: Motorcycle.
 * Ure-sen: A product that will be a big hit.
 * Wakka: Motorcycle (Bosozoku/Teamer)
 * Wappa: Handcuffs.
 * Yabai: Dangerous.
 * Yaku: Drug.
 * Yanki Gal/Boy: Girls or boyswith colored hair, earings, nail polish (for girls). This word has no relation to Yankii, or Americans.
 * Zako: Weak enemies, low-level Solos.

Yakuza Slang

 * Anko: A worker, or smuggling "mule".
 * Bon-naka: Gambling den.
 * Bon-ya: Bookie.
 * Chaka: Handgun.
 * Chimpira: Low-level Yakuza, identified by colorful "Big Suit" style.
 * Deiri: War (Between Yakuza families).
 * Dougu: Handgun (tool)
 * Eda: Branch of a Yakuza family.
 * Garasu-wari: To fire guns into an opponents window to scare or warm him.
 * Gasa-ire: A search by police.
 * Blank-gumi: Group (Most Yakuza clans/corporations are named with the family name + gumi. Example: Yamaguchi-gumi. These are listed on their buildings doorplates, or kamban).
 * Hine: Police.
 * Kamban-mochi: Formal member of a Yakuza family.
 * Kasuri: "Protection money" from shops and bars.
 * Katagi: Common people, non-Yakuza.
 * Koma-su: Win the heart of a woman, then dump her.
 * Mama: Pocket money; common event, thing, or person: easy job, O.K.
 * Mikajime-ryo: "Insurance Fee" from shops and bars.
 * Mom-mom: Tattoos.
 * Mori: Bodyguard.
 * Niwaba: Territory. (Tekiya)
 * Paku-rareru: Be arrested.
 * Paku-ru: Arrest.
 * Shaba: Common world, Outside of jail.
 * Shima: Territory, Also said as Shimamori.
 * Shinogi: Work, life, Income.
 * Tekiya: Street vendor, Stallman (or Ya-shi, "incense seller")
 * Teppo-dama: Hitman.
 * Tsutomeru: To go to jail for the family.
 * Yaru: To kill.

Korean Streeslang Influence
The lower-class, Cyberpunks, and Toseikai (yakuza-style mobsters) use Korean, with Japanese influences, to make it more offensive to listeners, and because many are second or third generation returnees from Japan.
 * Banchoppari: Mixed blood Korean-Japanese.
 * Cho/Choso: Communist, ex-North Korean, Terrorist.
 * Chongag: Bachelor.
 * Chap-sae: Goons, hired muscle, bodyguards.
 * Enyon: Japanese woman (derogatory)
 * Kyonchari: Policemen or Cops.
 * Noje: Slave, lower class, prole.
 * Paekch'i: Idiot, fool.
 * Pu: Money.
 * Sannomu: Idiot.
 * Sasaenga: Bastard, troublemaker.
 * Tou: Money.
 * Uenomu: Japanese man (derogatory)
 * Yain: Barbarian, uncouth person.
 * Yongsa: Hero.

Reference
PASQUARETTE, C. Pacific Rim Sourcebook. 1st ed. Berkeley CA: R.Talsorian Games, 1994