الَّذِي يُكَذِّبُ بِالدِّينِ
The one who rejects the reckoning and recompense. (107:1)
Alladhī is a relative noun; yukadhdhibu bi-l-dīn forms its relative clause. The condemned person is presented by the defining action of denial rather than by a personal name. This makes the description applicable to a recognizable pattern of conduct.
Dīn here is understood as judgment and recompense. Reading it without reference to the subsequent verses would obscure the connection with the acts of neglect and cruelty that follow.