Prohibitions 16-17

#16: “לא תחניפו את הארץ” This is a prohibition against flattery. It could apply to both the speaker and listener.
People who speak loshon hara might do it to find favor and flatter the listener. The person listening flatters the one who speaks loshon hara if he nodded his head in acquiescence or added a few words that adds to the slander. This sin’s severity causes Hashem’s Holy Presence to leave the Jews and it was one of the causes of the exile after the Second Temple was destroyed when the Sages flattered King Agripus.

#17 ״לא תקלל חרש״ A prohibition against cursing your fellow even if he is deaf or not present and all the more so if he can hear you curse him. Though this is not a part of lashon hara but many times when one gets angry and starts speaking lashon hara it leads to cursing the one he is speaking about.