What does Proverbs 18:5 mean?

In Hebrew, this statement literally says, "lifting the face of the wicked is not good." The same idea is then restated as setting aside righteous people in matters of judgment. To uphold evil and endorse those who are evil, at the expense of those who are moral, is a serious sin.

As a wise king and judge, Solomon practiced fairness on behalf of his subjects. He prosecuted the guilty and dispensed justice for the innocent. A judge may be tempted to distort justice on behalf of a wicked person because of that person's high status in society or because of his wealth or perhaps even out of fear of retribution. Scripture insists such an impulse is wrong. Just as wrong is to dismiss a righteous cause: to refuse to exonerate a poor or low-ranking member of society who is innocent. There are no excuses for the rendering of "perverted" or "twisted" justice (Proverbs 12:8; 17:23).

Someday Jesus, the Judge that stands at the door (James 5:9), will take possession of the earth, and He will rule "with justice and with righteousness" (Isaiah 9:7).