• أَسْرهُمْ
• أَسِير
• تَأْسِرُونَ

Appears 6 times in the Quran.

1. 2:85 ثُمَّ أَنتُمْ هَٰٓؤُلَآءِ تَقْتُلُونَ أَنفُسَكُمْ وَتُخْرِجُونَ فَرِيقًا مِّنكُم مِّن دِيَٰرِهِمْ تَظَٰهَرُونَ عَلَيْهِم بِٱلْإِثْمِ وَٱلْعُدْوَٰنِ وَإِن يَأْتُوكُمْ أُسَٰرَىٰ تُفَٰدُوهُمْ وَهُوَ مُحَرَّمٌ عَلَيْكُمْ إِخْرَاجُهُمْ أَفَتُؤْمِنُونَ بِبَعْضِ ٱلْكِتَٰبِ وَتَكْفُرُونَ بِبَعْضٍ فَمَا جَزَآءُ مَن يَفْعَلُ ذَٰلِكَ مِنكُمْ إِلَّا خِزْىٌ فِى ٱلْحَيَوٰةِ ٱلدُّنْيَا وَيَوْمَ ٱلْقِيَٰمَةِ يُرَدُّونَ إِلَىٰٓ أَشَدِّ ٱلْعَذَابِ وَمَا ٱللَّهُ بِغَٰفِلٍ عَمَّا تَعْمَلُونَ

   Yet you it is who slay your people and turn a party from among you out of their homes, backing each other up against them unlawfully and exceeding the limits; and if they should come to you, as captives you would ransom them-- while their very turning out was unlawful for you. Do you then believe in a part of the Book and disbelieve in the other? What then is the re ward of such among you as do this but disgrace in the life of this world, and on the day of resurrection they shall be sent back to the most grievous chastisement, and Allah is not at all heedless of what you do.
   

2. 8:67 مَا كَانَ لِنَبِىٍّ أَن يَكُونَ لَهُۥٓ أَسْرَىٰ حَتَّىٰ يُثْخِنَ فِى ٱلْأَرْضِ تُرِيدُونَ عَرَضَ ٱلدُّنْيَا وَٱللَّهُ يُرِيدُ ٱلْءَاخِرَةَ وَٱللَّهُ عَزِيزٌ حَكِيمٌ

   It is not fit for a prophet that he should take captives unless he has fought and triumphed in the land; you desire the frail goods of this world, while Allah desires (for you) the hereafter; and Allah is Mighty, Wise.
   

3. 8:70 يَٰٓأَيُّهَا ٱلنَّبِىُّ قُل لِّمَن فِىٓ أَيْدِيكُم مِّنَ ٱلْأَسْرَىٰٓ إِن يَعْلَمِ ٱللَّهُ فِى قُلُوبِكُمْ خَيْرًا يُؤْتِكُمْ خَيْرًا مِّمَّآ أُخِذَ مِنكُمْ وَيَغْفِرْ لَكُمْ وَٱللَّهُ غَفُورٌ رَّحِيمٌ

   O Prophet! say to those of the captives who are in your hands: If Allah knows anything good in your hearts, He will give to you better than that which has been taken away from you and will forgive you, and Allah is Forgiving, Merciful.
   

4. 33:26 وَأَنزَلَ ٱلَّذِينَ ظَٰهَرُوهُم مِّنْ أَهْلِ ٱلْكِتَٰبِ مِن صَيَاصِيهِمْ وَقَذَفَ فِى قُلُوبِهِمُ ٱلرُّعْبَ فَرِيقًا تَقْتُلُونَ وَتَأْسِرُونَ فَرِيقًا

   And He drove down those of the followers of the Book who backed them from their fortresses and He cast awe into their hearts; some you killed and you took captive another part.
   

5. 76:8 وَيُطْعِمُونَ ٱلطَّعَامَ عَلَىٰ حُبِّهِۦ مِسْكِينًا وَيَتِيمًا وَأَسِيرًا

   And they give food out of love for Him to the poor and the orphan and the captive:
   

6. 76:28 نَّحْنُ خَلَقْنَٰهُمْ وَشَدَدْنَآ أَسْرَهُمْ وَإِذَا شِئْنَا بَدَّلْنَآ أَمْثَٰلَهُمْ تَبْدِيلًا

   We created them and made firm their make, and when We please We will bring in their place the likes of them by a change.