(ن) سَاءَ يَسُوْءُ سَوْءًاsāʾa yasūʾu sawʾan (original form: سَوَءَ يَسْوُءُsawaʾa yaswuʾu): (1) (intransitive) to be disagreeable, to be bad, to go bad. ﴿وَسَآءَ سَبِيْلًا﴾ (An-Nisāʾ 4:22) (2) (transitive) to displease, to spoil something. ﴿اِنْ تَمْسَسْكُمْ حَسَنَةٌ تَسُؤْهُمْ﴾ (Āl ʿImrān 3:120)
اَسْوَاُaswaʾu feminine سُوْاٰىsūā (elative, ism tafḍīl): worse or worst. ﴿ثُمَّ كَانَ عَاقِبَةَ الَّذِيْنَ اَسَآءُوا السُّوْٓاٰى﴾ (Ar-Rūm 30:10)
سَوْءٌsawʾ and سُوْءٌsūʾ (adjective): bad, foul. ﴿عَلَيْهِمْ دَآئِرَةُ السَّوْءِ﴾ (At-Tawbah 9:98)
سَيِّئٌsayyiʾ feminine سَيِّئَةٌsayyiʾah: used both as a noun (ism dhāt) and as an adjective: evil, bad. ﴿وَجَزٰٓؤُا سَيِّئَةٍ سَيِّئَةٌ مِّثْلُهَا﴾ (Ash-Shūrā 42:40)
سَوْءَةٌsawʾah (noun, ism dhāt): a disagreeable thing; technically it is used for a human corpse and for the private parts. ﴿فَاُوَارِيَ سَوْءَةَ اَخِيْ﴾ (Al-Māʾidah 5:31)
Form IV (ifʿāl) اَسَاءَ يُسِيْءُ اِسَاءَةًasāʾa yusīʾu isāʾatan: to harm, to do evil. ﴿وَمَنْ اَسَآءَ فَعَلَيْهَا﴾ (Fuṣṣilat 41:46)