Saigu no omi-kotoba - Itsuki no omi-kotoba

...Originally, it was called "hidden words," but as a result of the use of the characters "hidden words," it came to be called "ingo," and it was also used as a translation of slang, making the meaning of "hidden words" more complex. Since hidden words are informal words that are only used among friends, they are not limited to those used by anti-social groups such as peddlers and criminals, but also include the "Itsuki no Miya Imikotoba" (Itsuki no miya imi kotoba) of the Heian period shrines (Araraki for towers, Kaminaga for monks, Nazu for uchi, etc.), the "Nyobo kotoba" (women's words) of court ladies (Oden for dengaku, Shamoji for shamoji, Okabe for tofu, etc.), the "Gakurin hikotoba" (Hidden words) of monks (Shironas for eggs, Kamisori for sweetfish, Gomasu for sake, etc.), the "Senbo" (Divination words) used by Osaka puppeteers (Sentarou for money, etc.), the "Oki kotoba" (Oki kotoba) of fishermen, and the "Yama kotoba" (Yama kotoba) of hunters, all of which can be considered hidden words in a broad sense. In addition, there are slang terms used in society by students, entertainers, merchants, doctors, the military, mountaineers, etc., but generally, slang terms often refer to code words used by antisocial groups.

*Some of the terminology explanations that refer to "Saigū no Ikotoba" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…元来は〈かくしことば〉といったが，隠語の字をあてられた結果〈いんご〉と呼ばれるようになり，スラングslangの訳語ともされて，隠語の意義内容は複雑になった。隠語は仲間うちだけに通用する目的の非公式の言葉であるから，香具師（やし）や犯罪者等の反社会的集団のものだけにかぎらず，平安時代の神宮の〈斎宮忌詞（いつきのみやいみことば）〉(塔をアララキ，僧をカミナガ，打つをナヅなど)，宮廷女官の〈女房言葉〉(田楽をオデン，杓子をシャモジ，豆腐をオカベなど)，僧侶の〈学林秘語〉(卵をシロナス，鮎をカミソリ，酒をゴマスなど)，大阪の人形遣いの用いた〈占傍（せんぼう）〉(金銭をセンタロウなど)，漁師の〈沖言葉〉や猟師の〈山言葉〉なども広い意味で隠語といえる。このほか，学生，芸能人，商人，医師，軍隊，山窩（さんか）などの社会で用いられる隠語もあるが，一般には隠語といえば反社会的集団の符丁言葉を意味することが多い。…

※「斎宮忌詞」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報