This study aims to examine the semantic development and customary restriction of a number of terms of al-Jarḥ wa al-Taʿdīl in Hadith sciences and to show how they move from their general linguistic meanings to their precise terminological meanings within the practice of Hadith critics. The study focuses on the way in which these terms acquire specialized meanings through their established use among scholars of Hadith criticism. The research material was divided into two main groups. The first comprised terms of commendation and authentication: “trustworthy,” “honest,” and “there is nothing wrong with him.” The second comprised terms of criticism and rejection: “deceitful,” “farsighted,” and “abandoned.” The study adopted an inductive and analytical approach to trace the meanings of these terms and determine their relationship to their original linguistic senses. The research concluded that Hadith terminology remains closely connected to its linguistic roots while being subject to precise customary restrictions that determine the status of the narrator in a positive or negative manner. It also revealed the distinctive features of certain critical schools, particularly Imam al-Bukhari’s specific usage of certain expressions, and demonstrated the effect of these terms on the acceptance of Hadith and its use as evidence and for corroboration.