Proverbs 17:20
A man of perverse heart does not prosper; he whose tongue is deceitful falls into trouble.

Perverse (definition) : Showing a deliberate and obstinate desire to behave in a way that is unreasonable or unacceptable.

A perverse heart is one when we deliberately behave in a way which is displeasing to God. (Hebrews 10:26,17) If we deliberately keep on sinning after we have received the knowledge of the truth, no sacrifice for sins is left, but only a fearful expectation of judgment and of raging fire that will consume the enemies of God.

(Proverbs 28:18) He whose walk is blameless is kept safe, but he whose ways are perverse will suddenly fall.

Application

Pray for our nation and pray for those who we know have a perverse heart. (Prov 11:20) The LORD detests men of perverse heart.