We may qualify something as Islamic if it is clearly understood from the Quran using the Arabic language to decode it.
Let me give three examples.

Example-1:
Using the Arabic Quran, one can read the following:

“اللَّهُ الَّذِي خَلَقَ السَّمَاوَاتِ وَالْأَرْضَ“

And we clearly understand from the above text that:
“It is Allah who created the heavens and the earth …” Quran 14:32
Hence “Allah is the one who created the heavens and the earth” is Islamic, for once you have learnt the basics of the Arabic language, you will clearly come to that understanding. However, you will also notice there is no ‘it’ in the original Arabic Quranic text, that it only contained one verb and that verb came after the word Allah. This means that a translation of the Arabic Quran may not match the original Arabic text, but may still convey a correct and valid understanding, but may not convey all the other valid meanings.

Example-2:
The Arabic Quranic text says:

” قُلْ هُوَ اللَّهُ أَحَدٌ
اللَّهُ الصَّمَدُ
لَمْ يَلِدْ وَلَمْ يُولَدْ
وَلَمْ يَكُن لَّهُ كُفُوًا أَحَدٌ “

One of its translations is as follows:
“Say, “He is Allah, [who is] One,
Allah, the Eternal Refuge.
He neither begets nor is born,
Nor is there to Him any equivalent.”” Quran 112
This translation is valid overall, but it does not match the original text.
Allow me to redo the original text using English words, Arabic words that do not have an equivalent in English, using the Arabic order of words and omitting any extra verbs:
“Say: “He Allah Ahad,
Allah AsSamad,
Not begot and not begotten,
And not have to him equivalent any.””
That is not English and so is the translation not Arabic.
For in the Arabic text, there are 3 verbs, but in the translation, there are 5 verbs.
Moreover, Ahad “أَحَدٌ” in this context is “One”, but without any association to “Two”, “Three” etc. He is unique in an absolute way.
Furthermore, Asammad has the meaning of “Eternal refuge”, but also the meaning of “void of emptiness” and “not compounded”. For compoundedness and emptiness are the qualities of creation.
It is Islamic to say that Allah has no children nor parents nor likeness.

Example-3:
From the Arabic Quran:

“وَوُضِعَ الْكِتَابُ فَتَرَى الْمُجْرِمِينَ مُشْفِقِينَ مِمَّا فِيهِ
وَيَقُولُونَ يَا وَيْلَتَنَا مَالِ هَٰذَا الْكِتَابِ لَا يُغَادِرُ صَغِيرَةً وَلَا كَبِيرَةً إِلَّا أَحْصَاهَا
وَوَجَدُوا مَا عَمِلُوا حَاضِرًا
وَلَا يَظْلِمُ رَبُّكَ أَحَدًا “

And from an English translation of the Quran:
” And the record [of deeds] will be placed [open], and you will see the criminals fearful of that within it, and they will say, “Oh, woe to us! What is this book that leaves nothing small or great except that it has enumerated it?” And they will find what they did present [before them]. And your Lord does injustice to no one. ” Quran 18:49
For this example, I shall skip the linguistic notes and focus on two understandings that are Islamic.
One, it is Islamic to say there is day of judgement and that Allah will judge all human beings for their deeds.
Two, it is also Islamic to say Allah will be fair to every human being and He will not wrong anybody.
In other words, Allah will be just with the theist and atheist, and He will even be just with the antitheist. That is Islamic. Hence injustice to anybody is non-Islamic.

to be continued …