Mudallis: A mudallis refers to a transmitter who (sometimes) transmits with obfuscation in his transmission; either intentionally or unintentionally narrating a hadith in manner that obscures or omits transmitters in the isnād.
Mukhtaliṭ refers to a transmitter who, on account of becoming senile, blind, or because of his books burning, is unable to transmit ḥadīth correctly anymore.
Mutābaʿāt (parallel narrations)
Majhūl al-ḥāl (integrity unverified) refers to a narrator who has more than one student who transmitted ḥādīths from him, but ḥadīth critics did not mention anything about his status as a narrator. In other words, a narrator whose reliability is externally evident, but about whose reliability nothing is known.
Mursal: A mursal ḥadīth is when a transmitter cites someone or the Prophet H without actually having met him.
Saraqah (the act of appropriating ḥadīth)
Saraqat al-ḥadīth: Equipping existing hadiths with one’s own chains of transmission or constructing entirely new chains of transmission was known as saraqat al-ḥadīth (stealing hadiths).
Shawāhid (witness narrations) are those aḥādīth that are narrated from a totally different chains of transmission (with a different Ṣaḥābī) but containing the same meaning as the ḥadīth in question and thus bolstering its reliability.
Tabiʿ (parallel narration)
Tawābiʿ (parallel narrations)
Tadlīs (obfuscates when he transmits)