Ḍaʻīf
Ibn Hajar described the cause of a hadith being classified as ḍaʻīf as "either due to discontinuity in the chain of narrators or due to some criticism of a narrator."
Ḍaʻīf, (ضَعِيْف), is the categorization of a hadith as weak. Ibn Hajar described the cause of a hadith being classified as weak as "either due to discontinuity in the chain of narrators or due to some criticism of a narrator." This discontinuity refers to the omission of a narrator occurring at different positions within the isnād and is referred to using specific terminology accordingly as discussed below.
Read more about this topic: Saheeh, Terminology Relating To The Authenticity of A Hadith