وأما الأداء القاصر: فهو تسليم عين الواجب مع النقصان في صفته
Deficient adāʾ is delivery of the original obligation while one of its qualities is deficient.
The original act or object has not been replaced: the shortcoming lies in a required quality. Hence this remains a form of adāʾ rather than qaḍāʾ.
Example 1: Prayer's basic acts are performed, but required composure in the postures is omitted.
Example 2: Circumambulation occurs with a relevant shortcoming concerning ritual purity.
Example 3: Property is returned but its legally significant quality or associated right has been impaired.