• ءَاسَفُونَا
• أَسَف
• أَسِف
• أَسَفىٰ

Appears 5 times in the Quran.

1. 7:150 وَلَمَّا رَجَعَ مُوسَىٰٓ إِلَىٰ قَوْمِهِۦ غَضْبَٰنَ أَسِفًا قَالَ بِئْسَمَا خَلَفْتُمُونِى مِنۢ بَعْدِىٓ أَعَجِلْتُمْ أَمْرَ رَبِّكُمْ وَأَلْقَى ٱلْأَلْوَاحَ وَأَخَذَ بِرَأْسِ أَخِيهِ يَجُرُّهُۥٓ إِلَيْهِ قَالَ ٱبْنَ أُمَّ إِنَّ ٱلْقَوْمَ ٱسْتَضْعَفُونِى وَكَادُوا۟ يَقْتُلُونَنِى فَلَا تُشْمِتْ بِىَ ٱلْأَعْدَآءَ وَلَا تَجْعَلْنِى مَعَ ٱلْقَوْمِ ٱلظَّٰلِمِينَ

   And when Musa returned to his people, wrathful (and) in violent grief, he said: Evil is it that you have done after me; did you turn away from the bidding of your Lord? And he threw down the tablets and seized his brother by the head, dragging him towards him. He said: Son of my mother! surely the people reckoned me weak and had well-nigh slain me, therefore make not the enemies to rejoice over me and count me not among the unjust people.
   

2. 12:84 وَتَوَلَّىٰ عَنْهُمْ وَقَالَ يَٰٓأَسَفَىٰ عَلَىٰ يُوسُفَ وَٱبْيَضَّتْ عَيْنَاهُ مِنَ ٱلْحُزْنِ فَهُوَ كَظِيمٌ

   And he turned away from them, and said: O my sorrow for Yusuf! and his eyes became white on account of the grief, and he was a repressor (of grief).
   

3. 18:6 فَلَعَلَّكَ بَٰخِعٌ نَّفْسَكَ عَلَىٰٓ ءَاثَٰرِهِمْ إِن لَّمْ يُؤْمِنُوا۟ بِهَٰذَا ٱلْحَدِيثِ أَسَفًا

   Then maybe you will kill yourself with grief, sorrowing after them, if they do not believe in this announcement.
   

4. 20:86 فَرَجَعَ مُوسَىٰٓ إِلَىٰ قَوْمِهِۦ غَضْبَٰنَ أَسِفًا قَالَ يَٰقَوْمِ أَلَمْ يَعِدْكُمْ رَبُّكُمْ وَعْدًا حَسَنًا أَفَطَالَ عَلَيْكُمُ ٱلْعَهْدُ أَمْ أَرَدتُّمْ أَن يَحِلَّ عَلَيْكُمْ غَضَبٌ مِّن رَّبِّكُمْ فَأَخْلَفْتُم مَّوْعِدِى

   So Musa returned to his people wrathful, sorrowing. Said he: O my people! did not your Lord promise you a goodly promise: did then the time seem long to you, or did you wish that displeasure from your Lord should be due to you, so that you broke (your) promise to me?
   

5. 43:55 فَلَمَّآ ءَاسَفُونَا ٱنتَقَمْنَا مِنْهُمْ فَأَغْرَقْنَٰهُمْ أَجْمَعِينَ

   Then when they displeased Us, We inflicted a retribution on them, so We drowned them all together,