HADITH TERMINOLOGY
مرسل
mursal
A Successor quotes the Prophet directly, skipping the Companion who would have heard it. A named link is missing.
A Successor (tābiʿī) says "the Messenger of God said…" without naming the Companion he received it from. Because the missing link is unnamed, that person's reliability cannot be assessed at all.
Ibn al-Ṣalāḥ restricts the term to the senior Successor who met and sat with Companions. Ibn Ḥajar defines it structurally: an omission at the end of the chain, after the Successor.
Scholars are genuinely split here. Al-Nawawī records: mursal is a weak hadith according to the great majority of hadith scholars, al-Shāfiʿī, and many jurists and legal theorists — while Mālik and Abū Ḥanīfa, along with a group, declared it sound. Ibn al-Ṣalāḥ quotes Muslim's introduction to his Sahih that mursal is not a proof. Al-Shāfiʿī himself accepted it where corroborated by another route. A separate case is mursal al-ṣaḥābī (a Companion reporting an event he did not personally witness), which on the correct view is judged sound.