The cognate accusative is known as mafʿūl muṭlaq (مفعول مطلق) in traditional Arabic grammar. In this syntactic role a noun will be found in the accusative case manṣūb (منصوب). The cognate accusative is used to add emphasis by using a verbal noun derived from the main verb or predicate that it depends on. Both the accusative and the verb will resonate phonetically as they will share the same root. In verse (80:25) below, the verbal noun (80:25:4) is a cognate accusative for the verb (80:25:2). The verbal noun is derived morphologically from the verb and both share the same root ṣād bā bā (ص ب ب):
Fig 1. Cognate accusative in verse (80:25).