It was a woman with a deep, sexual voice, talking about my boyfriend with obscene innuendos about our relationship.

obscene 是形容词，由前缀 ob-（表示"朝向"或"反对"）和词根 scene（场景）组成，原意是"令人反感的场景"，现在主要指"淫秽的、下流的"，形容言语或内容粗俗不雅。