Aḥādīth, when categorised according to the number of narrators, are of two types: mutawātir and khabr al-wāḥid.
Khabr al-wāḥid is any narration that does not meet the conditions of tawātur. It splits into three sub-categories: gharīb, ʿazīz and mashhūr.
Khabr āḥād is graded by acceptance into ṣaḥīḥ (li-dhātihī or li-ghayrihī), ḥasan (li-dhātihī or li-ghayrihī), and ḍaʿīf.
A ḥadīth is mardūd (rejected) when there is a break in the isnād or a criticism levelled at one or more of its narrators.
The Aḥnāf recognise three categories of aḥādīth (mutawātir, mashhūr, khabr wāḥid), while the muḥaddithīn recognise only two.
