Islam emphasizes that Muslims should have good names and give good names to their children. The Prophet (peace and blessings be upon him) is reported to have said, “You will be called on the Day of Resurrection by your names and the names of your fathers, so have good names.” (Reported by Abu Dawud).
Sheikh Muhammad Iqbal Nadvi, Imam of Calgary Mosque, Alberta, Canada, and former Professor at King Saud University, Riyad, Saudi Arabia, states the following: There is a difference between the unique attributes of Allah and common attributes. If we say Allah is `Alim, it means that Allah is the All-Knowing but this is also a common attribute among His servants, with the difference that Allah is the One above all knowledge.

But we say Allah is Khaliq meaning that Allah is the creator. This is not a common attribute that other people share with Allah. So it is called a unique attribute.
The first type is permissible to omit the word `Abd, while in the second case, it is only forgivable for the people that have no Islamic knowledge. However, for the people of knowledge, they should avoid naming their children with the exclusive attributes of Allah. Also, when we address a person, we should call him by the full name.