"He who winks his eyes does so to devise perverse things; he who compresses his lips brings evil to pass"
The key words in this verse both have the idea of compressing or shutting. Atsah is the first Hebrew word associated in this verse with eyes; to shut or to wink. The second is the word qarats which means to pinch, compress, or nip. Both words convey a similar meaning which can be translated into a signal that the person is in the business of doing that which will benefit them at the price of harm to others. Watch out for people who do this.
This is the Hebrew word raah which means that which violates God's standards but on a deeper level. It is that which is the pursuit of selfish desires to the point where harm or injury comes to others.
There is the idea in this verse that those who wink or squint or compress their eyes or lips are expressing a signal or an inner reality that they are hiding something. There is not an openness of spirit and soul to the person. The face does reflect openness when the spirit is not troubled, plotting, or bitter.
It is important to say that not everyone who ever winks or who purses their mouth is somehow evil or signaling evil. But the face does express in various ways what is going on in the soul.
Solomon also could be suggesting that there is universal facial expression language. This seems to be strongly suggested by recent scientists who traveled the world showing people from different cultures and pictures of different facial expressions and asking them what these expressions conveyed. The people were accurate over 90% of the time in being able to state what emotion was being expressed.
Each of the proverbs before and after this proverb states a characteristic to look for in people and then describes something much deeper if people will connect the dots. This idea is strange to our ears. Realize that the face is the reflection that is in the heart. What is in your soul will come out through your body and your face. It is the wise person who picks up on these cues. What is their face saying to you?