What are the criteria for weakening hadiths due to "Munkar (reprehensible) content in the text (matn)"?

A sound (sahih) hadith is one that meets five conditions: the uprightness of its narrators, their perfect precision, a continuous chain of transmission, and freedom from anomalousness (shudhudh) and defect (illah). If some of these conditions are not met, the hadith may be described as "denounced" (munkar). A "munkar" hadith is one narrated by a weak narrator who is unique in transmitting it, or one who contradicts a more reliable narrator. Critical imams may also apply the term to a hadith whose narrator's precision they doubt, whether the narrator is trustworthy or weak, based on indications such as his uniqueness in transmitting the report or his contradiction of reliable narrators. Ascertaining the denounced nature of a report requires gathering and studying its various chains of transmission. This is specific to scholars specialized in hadith, and it is not permissible for others to denounce a hadith based merely on opinion; otherwise, they would be following the path of the people of innovation.