Hasan li-dhatihi: adequate but lighter precision alongside uprightness, continuity, freedom from a damaging anomaly, and freedom from a disqualifying hidden defect. It can serve as evidence and varies in strength.
Sahih li-ghayrihi: a report intrinsically hasan reaches a higher grade through effective independent corroboration. Hasan li-ghayrihi arises when a compensable weakness is sufficiently supported. Mere numbers cannot repair every defect.
Al-Tirmidhi's composite terms: "hasan sahih" can reflect differing routes or critical assessments; "hasan gharib" combines grade and relative singularity; "ʿindana" may indicate particular usage.
The next distinct subject is ziyadat al-thiqah: under what conditions an addition reported by a reliable transmitter should be accepted.