淫いん事じいんじMeanings1nounlascivious act; lewd conductA formal or literary term for indecent or lewd behavior, often with a moralistic or legalistic tone. Rare in modern conversation.古こ文ぶん書しょには淫いん事じを戒いましめる記き述じゅつが見みられる。In old documents, one can find passages that warn against lascivious acts.