Hafidh literally meaning 'guardian', is a term used by 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...

s in modern days for someone who has completely memorized

Memorization

Memorization is the process of committing something to memory. The act of memorization is often a deliberate mental process undertaken in order to store in memory for later recall items such as experiences, names, appointments, addresses, telephone numbers, lists, stories, poems, pictures, maps,...

 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...

.
The prophet Muhammad

Muhammad

Muhammad |ligature]] at U+FDF4 ;Arabic pronunciation varies regionally; the first vowel ranges from ~~; the second and the last vowel: ~~~. There are dialects which have no stress. In Egypt, it is pronounced not in religious contexts...

 lived in the 7th century CE, in Arabia in a time when many people were not literate. The Arabs preserved their histories, genealogies, and poetry by memory alone. When Muhammad proclaimed the verses later collected as the Qur'an, his followers naturally preserved the words by memorizing them.

Early accounts say that the literate Muslims also wrote down such verses as they heard them.