What is the meaning of a Mursal Hadith and an Mu'an'an Hadith, and are they among the categories of Sahih (authentic) Hadith?

A mursal hadith is one that a Tabi'i (successor) traces back to the Prophet, peace and blessings be upon him. It is generally considered among the weak hadiths due to the unknown identity of the dropped narrator in the chain of transmission. Some scholars have, however, made an exception for the mursal hadiths of Sa'id ibn al-Musayyab. As for a mu'an'an hadith, it is one narrated by a reporter from someone he lived contemporaneously with, using the صيغة (formulation) "عن" (on the authority of). It is considered connected unless the narrator is a mudallis (one who practices tadlis, i.e., obscures the identity of a narrator or the fact that he did not directly hear the hadith). However, its authenticity is not conclusive unless its conditions of authenticity are met.