GOD'S WORD® Translation
Let [their] lying lips be speechless, since they speak against righteous people with arrogance and contempt.

American Standard Version
Let the lying lips be dumb, Which speak against the righteous insolently, With pride and contempt.

Berean Study Bible
May lying lips be silenced—lips that speak with arrogance against the righteous, full of pride and contempt.

Douay-Rheims Bible
Let deceitful lips be made dumb. Which speak iniquity against the just, with pride and abuse.

English Revised Version
Let the lying lips be dumb; which speak against the righteous insolently, with pride and contempt.

King James Bible
Let the lying lips be put to silence; which speak grievous things proudly and contemptuously against the righteous.

World English Bible
Let the lying lips be mute, which speak against the righteous insolently, with pride and contempt.

Young's Literal Translation
Let lips of falsehood become dumb, That are speaking against the righteous, Ancient sayings, in pride and contempt.

Psalm 31:18 Additional Translations ...