ش ک کsh-k-k
(ن) شَكَّ يَشُكُّ شَكًّاshakka yashukku shakkan (original form: شَكَكَ يَشْكُكُshakaka yashkuku): to doubt, to waver between two things; the original sense is of piercing and running through with a spear, and doubt was given this name because it pierces certainty.
شَكٌّshakk pl. شُكُوْكٌshukūk (noun, ism dhāt): doubt, wavering. 15 times in the Quran, every time as a noun (ism dhāt). ﴿وَاِنَّهُمْ لَفِيْ شَكٍّ مِّنْهُ مُرِيْبٍ﴾ (Hūd 11:110)