Al-Tirmidhi employs combinations such as hasan, sahih, gharib, hasan sahih, hasan gharib, sahih gharib, and hasan sahih gharib. They should not all be forced into one rigid formula without reference to context. The terms may address the degree of acceptance and the extent of known routes in different ways.
The word hasan in expressions such as "hasan gharib" or "hasan sahih" must not automatically be assumed to carry exactly the same restricted meaning as the later formal definition of intrinsic hasan in every occurrence. A critic's historical and individual use matters.
Assessing independent isnads and interpreting a scholar's brief technical vocabulary are two related but distinct intellectual tasks.
The precise limitation: Al-Tirmidhi defined a particular use of the unqualified designation hasan: the report does not contain a transmitter accused of lying, is not shadh, and is supported by transmission from another route. Ibn Hajar explains that this definition governs the relevant case in which al-Tirmidhi says hasan alone, not automatically compound expressions such as hasan sahih, hasan gharib, or hasan sahih gharib. Those combinations need separate consideration of context and routes.