أمي
Ummī
The Prophet is called ummī, “unlettered”, and the Quran uses ummiyyūn for the unlettered and for gentiles.
What it means
“Those who follow the Messenger, the unlettered prophet” (7:157). The Quran tells the Prophet: “You did not recite any book before it, nor write it with your right hand; otherwise those who follow falsehood would have doubted” (29:48). The Prophet said: “We are an unlettered nation; we do not write or calculate” (Sahih al-Bukhari), speaking of the Arabs. In 3:75 some of the People of the Book say “there is no blame on us in regard to the ummiyyīn”, a term for those who are not Jews.
Often misunderstood as
That the Prophet could not have known the stories of earlier prophets.
What the sources say
Muslims see the Prophet’s unlettered state as part of the sign of the Quran: it was not a work of a scholar. Some scholars say ummī means “from the Mother of Cities”, Mecca, or “of the nations”, and the sense is not disputed that he had no formal training in scripture.