ی ء سy-ʾ-s
(س) يَئِسَ يَيْاَسُ يَاْسًاyaʾisa yayʾasu yāsan: to lose hope, to despair. ﴿اِنَّهُۥ لَا يَايْـَٔسُ مِنْ رَّوْحِ اللّٰهِ اِلَّا الْقَوْمُ الْكٰفِرُوْنَ﴾ (Yūsuf 12:87); ﴿اَلْيَوْمَ يَئِسَ الَّذِيْنَ كَفَرُوْا مِنْ دِيْنِكُمْ﴾ (Al-Māʾidah 5:3)
يَئُوْسٌyaʾūs (intensive form (ṣīghat al-mubālaghah) on the pattern فَعُوْلٌfaʿūl): utterly despairing. ﴿وَاِنْ مَّسَّهُ الشَّرُّ فَيَئُوْسٌ قَنُوْطٌ﴾ (Fuṣṣilat 41:49)
Form X (istifʿāl) اِسْتَيْاَسَ يَسْتَيْئِسُ اِسْتِيْآسًاistayʾasa yastayʾisu istīāsan: synonymous with the bare triliteral (thulāthī mujarrad), to despair (completely). ﴿فَلَمَّا اسْتَيْـَٔسُوْا مِنْهُ خَلَصُوْا نَجِيًّا﴾ (Yūsuf 12:80); ﴿حَتّٰٓى اِذَا اسْتَيْـَٔسَ الرُّسُلُ﴾ (Yūsuf 12:110)