المعنى الاصطلاحي :

An attribute that describes the Essence only without any other characteristic.

الشرح المختصر :

"As-Sifah an-Nafsiyyah" (attribute of Allah's Essence) is a single attribute: Allah's existence. That is, Allah does exist, He is Self-Subsistent, and "Qadeem" (eternal/has no beginning) according to some of them. This attribute does not indicate anything that is not intrinsic of the essence. It is called thus because the essence could not be perceived except by expressing it through this attribute. Ahl-us Sunnah say that Allah's existence is not external to or separable from His essence. Rather, separation occurs in the human mind, not in reality. The "Sifāt an-Nafsiyyah" are part of the classification proposed by the Ash‘arites and their like. They did so because they considered the matters without which the human mind cannot perceive Allah's Essence and placed them under a category that they called "sifāt nafsiyyah". Undoubtedly, there is no entity that exists with an essence that can be lacking an essence. This, however, is not the case with attributing knowledge to Allah and describing Him as Knowledgeable. That is because His Essence could be perceived without being attached to His Knowledge. This perception, in fact, goes back to what they have presumed within themselves. Otherwise, when we consider the very issue, we come to know that all the attributes of the Lord that are intrinsic to His essence are "sifāt nafsiyyah dhātiyyah" (attributes related to His Essence and intrinsic to it). Allah is Knowledgeable with His Knowledge, Capable by Himself and His Essence, and Capable by His Capability. He has knowledge that is inseparable from His Essence and ability that is inseparable from His Essence. All this is not beyond the concept of the name given to His Being.