ثم الأداء نوعان: ١- كامل ٢- قاصر
Performance is of two kinds: complete and deficient.
Complete adāʾ supplies the very obligation with its required qualities and attendant rights. Deficient adāʾ supplies the original act or object but with a shortcoming in a required characteristic.
This is not a mere binary between valid and invalid acts. Some deficiencies may be remedied by an additional duty; other defects have different consequences. One must identify the particular missing quality.