Lewdness or lascivious behavior; sexual licentiousness, often used in a critical or literary sense.
彼は若い頃、淫奔な生活を送っていたという噂があった。
There were rumors that he led a licentious life in his youth.
伝記の筆者は、主人公の淫奔を批判的に描いている。
The biographer depicts the protagonist's licentiousness critically.