A Muslim is an adherent of Islam, a monotheistic, Abrahamic religion based on the Quran, which Muslims consider the verbatim word of God as revealed to prophet Muhammad. "Muslim" is the Arabic term for "one who submits to God".
Muslims believe that God is one and incomparable. Muslims also believe that Islam is the complete and universal version of a primordial faith that was revealed at many times and places before, including through the prophets Abraham, Moses and Jesus.
A Muslim is one who believes there is no God but Allah, and Muhammad (Peace be upon him) is his last messenger.