"The words of the wicked lie in wait for blood, but the mouth of the upright will deliver them"
This is the Hebrew word dabar which means words or speech or speaking. The idea here is that Solomon says that the intent of the person who is wicked is for someone to lose, to be hurt. One of the characteristics of wickedness is that this person gains through the loss of others. It is the win-lose way of negotiating and living.
Remember that the wicked person – according to the Old Testament – is one who lives outside of the Ten Commandments as a way of life. Lying is okay if it gets you what you want; stealing is okay as long as you get what you want; intimidation, physical violence – even murder – is okay as long as you get what you want; pretending to worship other gods is okay as long as you get what you want; sexual unfaithfulness is okay as long as you get what you want; planning and plotting how to take other people's possessions is okay as long as you win; open rebellion against authority is okay as long as you are living the life you really want. All of these are the components of a wicked life.
This is why Solomon says that underneath the speech of the wicked person is a motive for them to win and you to lose. In their minds, there is no looking for the win-win; they only focus on gain through other's loss.
The wicked use words to their advantage to get what they want; there are no boundaries to how they use words. They use them to serve their purposes and do harm to their opponents and others who have what they want.
Notice how carefully God says that the righteous person needs to be with what they say. The wicked person is trying to trip you up through their words or using your words. The righteous person will be delivered through their constant focus on what is right and good for everyone.
The righteous person will not participate in the schemes of the wicked. As soon as it becomes apparent that a plan is designed to rob others of their gains or possessions, then the righteous person is out. It doesn't matter how much the profit is or how easy it is or that someone else will just get the profit or gain. It matters that the gain comes by making other people hurt or wounded or lose.
When you are with a person, what do their words tell you as you read between the lines? Are they out for themselves? Are they twisting their words so that they profit while others lose? Is it clear that their intent is to hurt another or make them lose? This is a signal that you are dealing with a wicked person even though they may be a relative or close friend or respected person. If their words belie a waiting for blood, then the person is beyond the boundary of acceptable behavior in God's eyes. They are living a wicked life in some area or areas of their life.
You need to be extra careful with what you say and make sure you are looking for the triple-win. Does what you want to do really benefit the other person as well as you?