The Quran root ك ن ن k-n-n

وَمِنْهُم مَّن يَسْتَمِعُ إِلَيْكَ وَجَعَلْنَا عَلَىٰ قُلُوبِهِمْ أَكِنَّةً أَن يَفْقَهُوهُ وَفِي آذَانِهِمْ وَقْرًا وَإِن يَرَوْا كُلَّ آيَةٍ لَّا يُؤْمِنُوا بِهَا حَتَّىٰ إِذَا جَاءُوكَ يُجَادِلُونَكَ يَقُولُ الَّذِينَ كَفَرُوا إِنْ هَٰذَا إِلَّا أَسَاطِيرُ الْأَوَّلِينَ ٢٥

أَكِنَّةً akinnatan · coverings

And among them are those who listen to you, but We have placed over their hearts coverings, lest they understand it, and in their ears deafness. And if they should see every sign, they will not believe in it. Even when they come to you arguing with you, those who disbelieve say, "This is not but legends of the former peoples." (Surah Al-An'am, 6:25)

وَجَعَلْنَا عَلَىٰ قُلُوبِهِمْ أَكِنَّةً أَن يَفْقَهُوهُ وَفِي آذَانِهِمْ وَقْرًا وَإِذَا ذَكَرْتَ رَبَّكَ فِي الْقُرْآنِ وَحْدَهُ وَلَّوْا عَلَىٰ أَدْبَارِهِمْ نُفُورًا ٤٦

أَكِنَّةً akinnatan · coverings

And We have placed over their hearts coverings, lest they understand it, and in their ears deafness. And when you mention your Lord alone in the Qur’ān, they turn back in aversion. (Surah Al-Isra, 17:46)

كَأَنَّهُنَّ بَيْضٌ مَّكْنُونٌ ٤٩

مَّكْنُونٌ maknūnun · well protected

As if they were [delicate] eggs, well-protected. (Surah As-Saffat, 37:49)

وَلَا جُنَاحَ عَلَيْكُمْ فِيمَا عَرَّضْتُم بِهِ مِنْ خِطْبَةِ النِّسَاءِ أَوْ أَكْنَنتُمْ فِي أَنفُسِكُمْ عَلِمَ اللَّهُ أَنَّكُمْ سَتَذْكُرُونَهُنَّ وَلَٰكِن لَّا تُوَاعِدُوهُنَّ سِرًّا إِلَّا أَن تَقُولُوا قَوْلًا مَّعْرُوفًا وَلَا تَعْزِمُوا عُقْدَةَ النِّكَاحِ حَتَّىٰ يَبْلُغَ الْكِتَابُ أَجَلَهُ وَاعْلَمُوا أَنَّ اللَّهَ يَعْلَمُ مَا فِي أَنفُسِكُمْ فَاحْذَرُوهُ وَاعْلَمُوا أَنَّ اللَّهَ غَفُورٌ حَلِيمٌ ٢٣٥

أَكْنَنتُمْ aknantum · you conceal it

There is no blame upon you for that to which you [indirectly] allude concerning a proposal to women or for what you conceal within yourselves. Allāh knows that you will have them in mind. But do not promise them secretly except for saying a proper saying. And do not determine to undertake a marriage contract until the decreed period reaches its end. And know that Allāh knows what is within yourselves, so beware of Him. And know that Allāh is Forgiving and Forbearing. (Surah Al-Baqarah, 2:235)

وَاللَّهُ جَعَلَ لَكُم مِّمَّا خَلَقَ ظِلَالًا وَجَعَلَ لَكُم مِّنَ الْجِبَالِ أَكْنَانًا وَجَعَلَ لَكُمْ سَرَابِيلَ تَقِيكُمُ الْحَرَّ وَسَرَابِيلَ تَقِيكُم بَأْسَكُمْ كَذَٰلِكَ يُتِمُّ نِعْمَتَهُ عَلَيْكُمْ لَعَلَّكُمْ تُسْلِمُونَ ٨١

أَكْنَانًا aknānan · shelters

And Allāh has made for you, from that which He has created, shadows [i.e., shade] and has made for you from the mountains, shelters and has made for you garments which protect you from the heat and garments [i.e., coats of mail] which protect you from your [enemy in] battle. Thus does He complete His favor upon you that you might submit [to Him]. (Surah An-Nahl, 16:81)