ک س لk-s-l
(س) كَسِلَ يَكْسَلُ كَسَلًاkasila yaksalu kasalan: to be lazy, to be slack in a task. (This verb is not used in the Quran.)
كَسْلَانُkaslānu pl. كُسَالٰىkusālā (adjective on the pattern of فَعْلَانُfaʿlānu): very lazy, sluggish. ﴿وَاِذَا قَامُوْٓا اِلَي الصَّلٰوةِ قَامُوْا كُسَالٰى﴾ (An-Nisāʾ 4:142); ﴿وَلَا يَاْتُوْنَ الصَّلٰوةَ اِلَّا وَهُمْ كُسَالٰى﴾ (At-Tawbah 9:54)