Shaykh Mashhoor bin Hasan Aal-Salmaan(hafidhahullaah)
Are an-Naafi’, adh-Dhaar , al-‘Aarif  and al-Baaqee  from the Beautiful Names of Allaah, ‘Azza wa Jalla?
There is no established text from the Prophet, sallallaahu ‘alayhi wasallam, regarding these names. Therefore, it is not permissible for anyone to name after them such as ‘Abdul-Baaqee, ‘Abdun-Naafi? and the same applies for al-‘Aarif and adh-Dhaar.
And the ‘Ulamaa have absolutely prohibited the name al-‘Aarif for Allaah. Or that one should say when he is asked (something he doesn’t know) that instead of saying‘Allaahu a’lam’ (Allaah knows best), he says ‘Allaahu A’rif’. This is a statement of disbelief and it is not permissible.
This is because there is a difference in the (Arabic) language between al-‘Ilm(knowledge) and Ma’rifah (understanding). That is: Ma’rifah is preceded by al-Jahl(ignorance) whereas ‘Ilm is not preceded by Jahl. So if it said to you, ‘Allaah knows (ya’rifullaah)’, then it must be that Allaah was ignorant and thereafter understood!! So it is haraam (impermissible) for a Muslim to say, ‘Allaahu ya’rif‘ and he must (instead) say ‘Ya’lamillaah‘ (Allaah knows best).
Therefore, al-‘Aarif is not from the names of Allaah and this is agreed upon by the consensus of the people of knowledge. Amongst them ibn al-Lihhaam in his book al-Mukhtasar in page 36 (in which) he states; ‘And He is not described, Glory be to Him, by His being ‘Aarif. So whoever says this out of ignorance then he has not apostated and he is pardoned by (his) ignorance. But if he is not pardoned by ignorance, then he is not free from sin.’
Shaykh Mashhoor bin Hasan aal-Salmaan
 al-Naafi’ comprises several meanings amongst them; The Most Beneficial, The Most Advantageous.
 adh-Dhaar; The Most Harmful, The Most Injurious.
 al-‘Aarif; The Most Acquainted, The Most Conversant.
 al-Baaqee; The Remaning, The Everlasting.
* Although some of these terms might have a meaning that is somehow similar to authentically proven names and attributes of Allaah; still we cannot use them as they are not established. And as Our religion is perfect; we suffice ourselves with authentic texts.
Source : 100 Fataawa of Shaykh Mashhoor Hasan, Fatwa Number 21
Translation by :Umm ‘Aaishah