"A righteous man hates falsehood, but a wicked man acts disgustingly and shamefully"
This is the word saddiq which means just, lawful, righteous. It means conforming to an ethical or moral standard. It would be, in this case, that the person stays within the boundaries of the Ten Commandments and performs the positive demands which are in most cases the opposite of the Ten Commandments. This was the righteous person in the Old Testament.
It must be added that even in the Old Testament it was clear that no one did this perfectly enough to earn their way into God's favor. That is why there was a sacrificial system which atoned for their sins or lack of righteousness.
This is the word seqer which means lie or falsehood; that which is not true or is a fraud. This would include the breaking of a promise and deceit.
This is the word sinah which means hatred, disgust. It is a strong emotional reaction of opposition and disgust towards something to be avoided and despised; something that is altogether unappealing.
Solomon is telling us something very valuable when he describes the behavior of the person who is righteous because in our day we have strayed so far from righteousness, we are not used to a virtuous person when we see one. God tells us, through Solomon, that the righteous person will have a natural aversion or emotional reaction to fraud, deceit, lying. They will not be able to easily go along with it or hear about it without a reaction. They will not participate in it.
This insight is important as we constantly have to evaluate people we meet or intend to hire or want to become deeper friends with. Solomon proposes a test: what is their reaction to lying, falsehood, or deceit.
Another application of this insight is to gauge your reaction to deceit, fraud, lies. Have you participated in these things? Do you regularly deceive people? How do you react when people tell of practical jokes they pulled on people? What is your reaction when someone says that they deceived a person in business?
If this is no big deal or if it is a part of life or a part of business, then you need to come to grips with the fact that you do not understand righteous living or Christ-like living. It most likely means that you have not allowed God to work on your speech patterns so that they are positive and encouraging. It may mean that your goals are off and that money, fame, and power are still too much what you are after instead of the glory of God. Don't be fooled; righteous people do not like being in the presence of lying.
but a wicked man acts disgustingly and shamefully
Wickedness is the Hebrew word rasa which means those who continually do wrong; those who live outside the boundaries of the Ten Commandments. Remember that it is possible to violate one of the commandments and then admit that it was wrong and get back inside the moral boundaries. But the wicked person is the one who no longer recognizes the commandment as a boundary they will abide by; in this case, specifically, they no longer respect the ninth commandment: Thou shalt not bear false witness against thy neighbor.
But it is also true that wickedness or living beyond God's moral boundary structure embraces falsehood and lying. They think nothing of deceiving people to get what they want. I know a number of people who would not want to admit that they are wicked because they would say that they generally tell the truth, but they would not have any difficulty deceiving someone to get what they want. This is wickedness. If you are not willing to stop your behavior because of God's boundaries, then God defines this as wickedness. If you are willing to lie to your husband or wife to get some item or activity you want; if you are willing to lie to your boss or a customer to get what you want; if you are willing to lie to your parents or your teachers to get what you want – then you have sinned and allowed selfishness to win. Repent and thank God for the forgiveness that is in Jesus Christ's death on the cross. Be willing to not get what you want so that God will get glory.