«غَرِيبُ الْحَدِيثِ»
Here, gharīb al-ḥadīth concerns rare, unfamiliar, or little-used words in the wording of a hadith, whose sense requires linguistic explanation.
“Gharīb” in this context is not a claim about how many narrators transmitted a report. A gharīb report concerns uniqueness in a chain; gharīb al-ḥadīth addresses the language of the matn and how to understand it.
To investigate an unfamiliar word, scholars consider its correct reading, classical Arabic use, possible senses, and context. Even when a report is transmitted accurately, a mistaken interpretation of a single rare expression can produce an erroneous explanation.