«زَيِّ الْقُطَطْ يِقْرُوا مِنْ غِيرْ عِلْمْ»

The proverb targets a person who has no real knowledge yet wants to be taken for a learned one. Their method is to read a great deal, but the material they work through is beyond their comprehension, so the reading leaves them as uninformed as before.

By likening such a reader to cats, the saying presents the reading as empty of understanding. However much material has been covered, the quantity is treated as no evidence of learning, and the claim to knowledge built on it is exposed as hollow.

Aim it at someone who claims expertise because of how much they have read, when it is plain they have not understood that material. Since it calls the person ignorant, it is disparaging, especially if said to their face, and is unsuited to courteous exchanges.