can you please explain to me what's ummi means? i do really wants to know ur view about it 
it is a good question
i think we can respond ourselves, while reading the context where ummi is used in Quran
2:78 And among them are "
ummis" who do not know the Book except by hearsay, and they only conjecture.
3:20 If they debate with you, then say: "I have submitted myself to God, as well as those who follow me." And say to those who have received the Book and to "
ummis": "Have you submitted?" If they have submitted then they are guided, and if they turn away, then you are only to deliver, and God is Seer over the servants.
3:75 And from among the people of the Book are those whom if you entrust him with a large amount he gives it back to you, and there are those whom if you entrust with one gold coin he will not return it to you unless you are standing over him. That is because they said: "We have no obligation towards the "
ummis"" They say about God lies while they know.
7:157 "Those who follow the "
ummi" messenger prophet whom they find written for them in the Torah and the Gospel; he orders them to kindness, and prohibits them from vice, and he makes lawful for them the good things, and he makes unlawful for them the evil things, and he removes their burden and the shackles that are upon them. So those who believe in him, and support him, and help him persevere, and follow the light that was sent down with him; these are the successful ones."
7:158 Say: "O people, I am a messenger of God to you all. The One who has the sovereignty of the heavens and the earth, there is no god except He; He gives life and causes death." So believe in God and His "
ummi" messenger prophet, who believes in God and His words; and follow him that you may be guided.
62:2 He is the One who sent to the "
ummis" a messenger from among themselves, to recite to them His revelations, and to purify them, and teach them the Book and the wisdom. And before this, they were clearly astray.
