This verse focuses on the “fool” and suggests nothing good comes out of any connection with him. Certainly, you can’t expect “knowledge on their lips” or them to say anything of value. Hanging around with him will do no good.
This is not really new information for any of us – mom’s been telling us this kind of stuff since we were kids! My grandma used to say, “lay down with dogs and you will get up with fleas!”
Remember that the Biblical description of fools is their refusal to accept God as part of their world view (Psa 14:1). That is the root cause of their issues and, while they have the right to live and think that way, it’s also why we should “stay away from a fool.”
The real key for us is identifying the fool in our daily interactions and then extricating ourselves from getting too caught up with them. Admittedly, if they are in our family or we have to work with them it is more complicated. In the end, we just need to realize with whom we are dealing and respond appropriately.