3 The words of their mouths are wicked and deceitful; they fail to act wisely or do good.

Read Psalm 36:3 Using Other Translations

The words of his mouth are iniquity and deceit: he hath left off to be wise, and to do good.
The words of his mouth are trouble and deceit; he has ceased to act wisely and do good.
Everything they say is crooked and deceitful. They refuse to act wisely or do good.