Mumin redirects here. See Moomin

Moomin

The Moomins are the central characters in a series of books and a comic strip by Swedish-Finn illustrator and writer Tove Jansson, originally published in Swedish by Schildts in Finland. They are a family of trolls who are white and roundish, with large snouts that make them resemble hippopotamuses...

 for the children's fiction.

Mūʾmin is an Arabic

Arabic language

Arabic is a name applied to the descendants of the Classical Arabic language of the 6th century AD, used most prominently in the Quran, the Islamic Holy Book...

 Islam

Islam

Islam . The most common are and .   : Arabic pronunciation varies regionally. The first vowel ranges from ~~. The second vowel ranges from ~~~...

ic term frequently referenced in the Qur'an

Qur'an

The Quran , also transliterated Qur'an, Koran, Alcoran, Qur’ān, Coran, Kuran, and al-Qur’ān, is the central religious text of Islam, which Muslims consider the verbatim word of God . It is regarded widely as the finest piece of literature in the Arabic language...

, literally meaning "believer", and denoting a person that has complete submission to the Will of Allah

Allah

Allah is a word for God used in the context of Islam. In Arabic, the word means simply "God". It is used primarily by Muslims and Bahá'ís, and often, albeit not exclusively, used by Arabic-speaking Eastern Catholic Christians, Maltese Roman Catholics, Eastern Orthodox Christians, Mizrahi Jews and...

, and has faith firmly established in his heart, i.e. a "faithful Muslim".

In the Qur'an it is stated:
The Arabs of the desert say, "We believe." (tu/minoo) Say thou: Ye believe not; but rather say, "We profess Islam;" (aslamna) for the faith (al-imanu

Iman (concept)

Iman is an Arabic term which denotes certitude or adherence to an idea. In Islamic theology, it refers to the inner aspect of the religion, and denotes a believer's faith in the metaphysical realities of Islam. The term Iman has been delineated in both the Quran as well as the famous Hadith of...

) hath not yet found its way into your hearts. But if ye obey God and His Apostle, He will not allow you to lose any of your actions: for God is Indulgent, Merciful.

That verse makes a distinction between a Muslim

Muslim

A Muslim, also spelled Moslem, 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 "submitter" .Muslims believe that God is one and incomparable...

and a believer.

Also:
O you who believe! Believe in Allah, and His Messenger (Muhammad), and the Book (the Quran) which He has sent down to His Messenger, and the Scripture which He sent down to those before (him), and whosoever disbelieves in Allah, His Angels, His Books, His Messengers, and the Last Day, then indeed he has strayed far away.
That verse addresses the believers, exhorting them to believe, implying multiple stages of belief.