«أَنَّ الشَّاذَّ مَا رَوَاهُ الْمَقْبُولُ مُخَالِفًا لِمَنْ هُوَ أَوْلَى مِنْهُ»
A shadh report is transmitted by an otherwise accepted narrator in contradiction to someone whose version has stronger grounds for preference.
Maqbul includes transmitters generally treated as acceptable, such as reliable or truthful narrators. The issue is not simply that the person narrated alone; the relevant report conflicts with a superior version.
The crucial inquiry is whether the transmission merely differs in detail or genuinely contradicts a more accurately preserved report. Shudhudh in this formulation depends on establishing the latter.