- Kafir - is derived from the word - Kufr - , which means to conceal or to reject. In Islamic terminology, - Kafir - means one who conceals or rejects the truth of Islam and a person who rejects Islam is in English called a non-Muslim.
Are you Muslim or Non-Muslim? calling non-Muslim to Non-Muslim is anything wrong?
If any non-Muslim considers the word - Kafir - i.e. - non-Muslim - as an abuse, he may choose to accept Islam and then we will stop referring to him as or call him a kafir i.e. a non-Muslim.