The Messenger of Allah (ﷺ) said:

“The believer does not slander, 
curse, 
or speak in an obscene 
or foul manner.”

Narrated by al-Tirmidhi (1977); classed as saheeh by al-Albaani in Saheeh al-Tirmidhi.

قال رسول الله (ﷺ) : 

" ليس المؤمن بالطعان، ولا اللعان، ولا الفاحش، ولا البذي "
رواه الترمذي