[1]. Who persist in denying Allāh, His messengers, and the Last Day.
The word kāfir which is translated as a disbeliever or denier comes from the root "K-F-R" (كَفَرَ) which literally means: To cover, conceal, or bury. It was used in pre-Islamic Arabic for farmers, because they cover seeds with soil, "like rain whose growth pleases the farmers (al-kuffār)" — Qur'an 57:20
So a kāfir is someone who covers up something — in the Qur’anic context, covers up the truth.
Allāh is the Creator of all people, and He judges by truth. He does not favor anyone by label, but supports the righteous, the sincere, the just, regardless of race or region or nationality.
"Indeed, the most honored of you in the sight of Allāh is the most righteous among you." Surah Al-Hujurat 49:13
So who is not kafir?
Anyone who believe in one god i.e., Allāh alone as creator of universe and submit to Him and following His messenger, the Prophet Muhammad.