Assalaamu alaykum. Some people have names that are taken from the names of Allaah like, for example, "Kabir". If someone insults another guy named "Kabir" by mocking his name, is that merely a sin then, or is it tantamount to Kufr (disbelief), as it is Allaah's name? It is to be noted that the object of insult was not Allaah's name but the name of the person. I am asking this because we are angry sometimes and might insult someone by mocking their name and then afterwards find out that it is also one of the names of Allaah.

All perfect praise be to Allah, The Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad is His slave and Messenger.

This name is among the common names (not specific to Allah Almighty), so it is permissible to name a person with it. Please, refer to fatwa 88517. Mocking the person or his name is not the same as mocking the Name of Allah, the Exalted, so the person who does this [mocks] does not become a disbeliever.

However, a Muslim should avoid mocking other people, as this is forbidden in Islam. Allah says (what means): {O you who have believed, let not a people ridicule [another] people; perhaps they may be better than them; nor let women ridicule [other] women; perhaps they may be better than them. And do not insult one another and do not call each other by [offensive] nicknames. Wretched is the name of disobedience after [one's] faith. And whoever does not repent - then it is those who are the wrongdoers.} [Quran 49:11]

For more benefit, please refer to fatwas 115714 and 86381.

It is more appropriate for a Muslim to be concerned with what benefits him in his religion and worldly matters.

Allah knows best.