ص و ب (ṣād wāw bā) arabic root word meaning.

to pour forth, hit the mark, come down. asaaba - to overtake, happen to, befall, fall upon, will, affect injuriously, meet with, send down, pour down upon, afflict or punish, intend, desire. sawaabun - that which is right, straight forward course, rightness. musiibun - that which happens. musiibatun - calamity.Lane: "...it poured forth (said of rain), it descended, a calamity that falls upon or becomes settled/fixed..."Asaaba (prf. 3rd. p.m. sing. IV): He befell, hitted.Asaabat (prf. 3rd. p. f. sing. IV.): She befell, afflicted.Asabtum (prf. 2nd. p.m. plu. IV.): You inflicted, smited.Asabna (prf 1st. p. plu. IV). We inflicted.Yusiibu/Yusiiba (nom./acc.)Yusib (juss./imp. 3rd. p.m. sing. IV.): Shall befall; Will afflict.Tusiibu/Tusiiba (nom./acc.)Tusib (juss./imp. 3rd. p. f ): It will befall.Tusiibanna (imp. 3rd. p. f. emp.): Shall afflict.Tusiibuu (imp. 2nd. p. m. plu. acc. IV.): You afflict, hurt, harm.Usiibu (imp. 1st. p. sing. IV.): I shall afflict.Nusiibu (imp. 1st. P. plu. IV.): We bestow (our mercy).Musiibun (ap-der. m. sing. IV.): That which to smite.Musiibtun (ap-der. f. sing. IV.): Affliction; Calamity.Sayyibun (n.): Heavy downpour.Sawaaban (n. acc.): Right.