Khabar al-wāḥid is any narration that does not meet the conditions of tawātur. It yields presumption (ẓann), and has three sub-categories by number of narrators.
The rejected report falls into two kinds: that rejected because of an omission in the isnād, and that rejected because of criticism of the narrator.
When the narrators' names are the same but their fathers' names differ, or vice versa, this is al-mutashābih; from it and the preceding categories various sub-types are formed.
An omission of two or more consecutive narrators at any point in the chain — this is al-muʿḍal.
