مَا لَكَ وَزَيْدًا؟
Translation: What business do you have with Zayd?
مَا: interrogative pronoun, topic in nominative position.
لَكَ: preposition lām plus second-person pronoun; prepositional predicate.
وَ: wāw of accompaniment.
زَيْدًا: accusative mafʿūl maʿahu related to the understood verbal sense.
Contrast the genitive coordinated ʿAmr in the previous example with the accusative accompaniment Zayd here.