According to the Grammarians (Sufi Terminology)

According to the grammarians, these are asmāʾ nuʿūtiyya (names related to attributes). The first category of names are essential names. These include names such as Aḥad, Wāḥid, Fard, Ṣamad, ʿAẓīm, Ḥayy, ʿAzīz, Kabīr, Mutaʿāl, and others of this kind. The second category of names are attributive names. This is the case whether they derive from substantive attributes such as ʿilm (knowledge) and qudra (power), or from active names such as Muṭīʿ and Khallāq. In the divine attributes, the essence of the description is His name al-Raḥmān. For the name al-Raḥmān, in terms of its comprehensiveness and inclusivity, corresponds to the name Allah. The difference between them is as follows: al-Raḥmān, in terms of its content and universality, ...