One of the methods the Quran utilizes to clarify the meaning of words is by means of providing contrasting examples such that one can understand the meaning of something by understanding its opposite.
[39:23] GOD has revealed herein the best Hadith; a book that is consistent and points out contrasting pairs. The skins of those who reverence their Lord cringe therefrom, then their skins and their hearts soften up for GOD’s message. Such is GOD’s guidance; He bestows it upon whomever He wills. As for those sent astray by GOD, nothing can guide them.
ٱللَّهُ نَزَّلَ أَحْسَنَ ٱلْحَدِيثِ كِتَـٰبًا مُّتَشَـٰبِهًا مَّثَانِىَ تَقْشَعِرُّ مِنْهُ جُلُودُ ٱلَّذِينَ يَخْشَوْنَ رَبَّهُمْ ثُمَّ تَلِينُ جُلُودُهُمْ وَقُلُوبُهُمْ إِلَىٰ ذِكْرِ ٱللَّهِ ذَٰلِكَ هُدَى ٱللَّهِ يَهْدِى بِهِۦ مَن يَشَآءُ وَمَن يُضْلِلِ ٱللَّهُ فَمَا لَهُۥ مِنْ هَادٍ
| 1 | al-lahu | ٱللَّهُ | God |
|---|---|---|---|
| 2 | nazzala | نَزَّلَ | He revealed |
| 3 | aḥsana | أَحْسَنَ | (the) best |
| 4 | l-ḥadīthi | ٱلْحَدِيثِ | [the] Hadith, |
| 5 | kitāban | كِتَـٰبًا | a book (of) |
| 6 | mutashābihan | مُّتَشَـٰبِهًا | similar / comparative / figurative / consistent |
| 7 | mathāniya | مَّثَانِىَ | contrasts / pairs. |
This is precisely what we find in the last verse that uses the word ummy, where it provides its exact definition by providing the definition of its opposite.
[3:20] If they argue with you, then say, “I have simply submitted myself to GOD; I and those who follow me.” You shall proclaim to those who received the scripture, as well as the ummyeen, “Would you submit?” If they submit, then they have been guided, but if they turn away, your sole mission is to deliver this message. GOD is Seer of all people.
فَإِنْ حَاجُّوكَ فَقُلْ أَسْلَمْتُ وَجْهِيَ لِلَّهِ وَمَنِ اتَّبَعَنِ وَقُلْ لِلَّذِينَ أُوتُوا الْكِتَابَ وَالْأُمِّيِّينَ أَأَسْلَمْتُمْ فَإِنْ أَسْلَمُوا فَقَدِ اهْتَدَوْا وَإِنْ تَوَلَّوْا فَإِنَّمَا عَلَيْكَ الْبَلَاغُ وَاللَّهُ بَصِيرٌ بِالْعِبَادِ
| 9 | waqul | وَقُل | And say |
|---|---|---|---|
| 10 | lilladhīna | لِّلَّذِينَ | to those who |
| 11 | ūtū | أُوتُوا۟ | [they] were given |
| 12 | l-kitāba | ٱلْكِتَـٰبَ | the book / scripture, |
| 13 | wal-umiyīna | وَٱلْأُمِّيِّـۧنَ | and the gentiles, |
| 14 | a-aslamtum | ءَأَسْلَمْتُمْ | “Would you [all] submit?” |
Notice that this verse contrasts those who were given the scripture ( لِلَّذِينَ أُوتُوا الْكِتَابَ ) with those who were not (wal-umiyīna / وَالْأُمِّيِّينَ ). This is a typical mechanism in the Quran where God contrasts two subjects so that we can recognize each group by its opposite. So, in this case, the opposite of “those who were given scripture” would not be “the illiterates” but “the gentiles.”
Additionally, if we apply the meaning of “illiterate” to the use of (wal-umiyīna / وَالْأُمِّيِّينَ ) in the above verse, then this would imply that Submission is only for the people of the scripture and the illiterates. This, again, would be an inaccurate interpretation as the Quran is a message to the whole world. This is encompassed in the final verse of Sura 68, The Pen (Al-Qalam / الـقـلـم ), which starts with the idea of writing and ends with claiming that the Quran is a message to the whole world.:
[68:1] NuN, the pen, and what they (the people) write.
نون وَٱلْقَلَمِ وَمَا يَسْطُرُونَ
[68:52] It is in fact a message to the world.
وَمَا هُوَ إِلَّا ذِكْرٌ لِّلْعَـٰلَمِينَ
Taken from: https://qurantalk.gitbook.io/muhammad-was-not-illiterate/ummy-illiterate/3-20-ummy-defined