indecent language; dirty talk
Refers to sexually explicit or lewd speech; often used in contexts like phone sex, erotic fiction, or describing vulgar remarks.
He whispered dirty talk over the phone.
その小説には淫語が多用されている。
That novel is full of indecent language.
Compound of 淫 (indecent, lewd) and 語 (word, language). The exact historical derivation is uncertain, but the kanji combination directly conveys the meaning.