Adding a qualifier (waṣf) to the subject may distinguish it from competitors. In “زَيْدٌ التَّاجِرُ عِنْدَنَا” (Zayd the merchant is with us), “merchant” can identify which Zayd is intended when more than one person shares the name.
Qualification can also supply praise, blame, stronger specification or reinforcement. The following expression stresses that the day has gone by:
أَمْسِ الدَّابِرُ كَانَ يَوْمًا عَظِيمًا
Yesterday, now past, was a momentous day.
A modifier and an independent predicate are different: “Zayd the merchant” identifies, whereas “Zayd is a merchant” asserts a judgment. The next section develops confirmation, substitution, coordination and related forms of presenting the subject.