HADITH TERMINOLOGY
مصطلح الحديث
muṣṭalaḥ al-ḥadīth
A scholar's verdict on how soundly a report reached us — a judgement about its chain of transmission, not about its meaning.
Every hadith reaches us through a chain of people who passed it on, one to the next, across centuries. Hadith science works by examining that chain: whether it is unbroken, and whether each person in it was both upright and accurate in retention.
So a grading attaches to a CHAIN, not to a text. Al-Nawawī puts it directly: if you see a hadith with a weak chain, say "it is weak by this chain" — do not say the text itself is weak merely because that one chain is weak, unless an authority states it was never narrated by any sound route.
Two different questions are often confused. "How reliable?" is answered by sahih, hasan, daif, mawdu'. "Attributed to whom?" is answered by marfu' (the Prophet), mawquf (a Companion), maqtu' (a Successor). A report can be both mawquf and sahih — these are not opposites.
This app never grades anything itself. It only reports rulings others have published, together with who issued them.
The standing of Sahih al-Bukhari and Sahih Muslim is itself debated. Ibn al-Ṣalāḥ held that their hadiths yield certain (qaṭʿī) knowledge. Al-Nawawī records that the verifying scholars and the majority disagreed with him, holding that they yield ẓann — strong probability — unless a report is mutawātir. Note also that the judgement applies to the connected narrations in them, not to every line of the books, and that a hadith's absence from them means nothing, since neither author set out to collect all authentic hadith.