Ardhal al-ʿumr is a Qur’anic expression referring to one of the final stages of human life, marked by a decline in certain capacities. In Qur’an 16:70 and 22:5, this stage is associated with a diminished ability to benefit from previous knowledge and understanding. However, exegetes differ concerning its precise meaning, its relation to physical aging and cognitive decline, and the conditions under which it occurs. This study provides a conceptual and exegetical analysis of ardhal al-ʿumr within the Qur’anic discourse, focusing on its physical and cognitive dimensions. Using a descriptive-analytical approach and lexical and exegetical sources, it examines the semantic implications of the root r-dh-l, its Qur’anic usages, and exegetical views on the nature of ardhal al-ʿumr, its age of occurrence, cognitive decline, and scope. The findings indicate that ardhal al-ʿumr refers to a stage of human life associated with natural weakness and declining physical capacities, particularly cognitive abilities; thus, no specific age constitutes its definitive criterion. Reports identifying ages such as seventy-five, eighty, or ninety indicate common instances rather than fixed thresholds, while the principal criterion is the decline of human capacities. Cognitive decline is neither an independent meaning of the expression nor a designation for a specific disease, but one of its significant manifestations. Analysis of the Qur’anic contexts further shows that, unlike al-arādhil, which reflects erroneous human standards of social value, ardhal al-ʿumr denotes a natural stage of human life and signifies the inherent limitations of human existence in relation to divine power and providential governance.