An accepted report, if it is free of any other accepted report contradicting it, even apparent contradiction, is al-muḥkam (literally, firmly established).
If another accepted report contradicts it, it is mukhtalaf al-ḥadīth.12
Mukhtalaf al-ḥadīth refers to a contradiction between two ḥadīths. Mushkil al-ḥadīth, by contrast, refers to an accepted ḥadīth that contradicts another piece of evidence, such as the Qurʾān or the ijmāʿ of the Companions. Some scholars treat the two terms as synonymous. It may also be noted that when a ḍaʿīf narration runs counter to a ṣaḥīḥ or ḥasan one, that too is sometimes called mukhtalaf al-ḥadīth. [tr.] ↩
An example: the ḥadīth "There is no contagion and no evil omen," alongside the ḥadīth "Flee from the leper as you flee from the lion." Their outward sense suggests contradiction. Sharḥ al-Nukhba, p. 44. ↩
If any one of the attributes of the ṣaḥīḥ or the ḥasan is missing, the ḥadīth is ḍaʿīf (literally, weak).
If the narrators of a ḥadīth agree in their wording of transmission, in any verbal feature, in an action, or in some shared quality, this is al-musalsal (literally, a chained or serial ḥadīth).
A ḥadīth in which a narrator has been replaced with another, whether one narrator, several, or even the entire chain, is al-maqlūb (literally, that which has been inverted).
When each of two peers narrates from the other, this is al-mudabbaj (literally, embellished or paired); al-ʿIrāqī, following al-Dāraquṭnī, did not require the two narrators to be peers.
