Impropriety and Porn

Impropriety noun - The quality or state of not being socially proper.

Porn and impropriety are semantically related In some cases you can use "Porn" instead a noun "Impropriety".

Porn noun - Creative activity (writing or pictures or films etc.) of no literary or artistic value other than to stimulate sexual desire.

Impropriety and porn are semantically related in obscenity topic. Sometimes you can use "Impropriety" instead a noun "Porn", if it concerns topics such as indecency.