What is the meaning of the word "maqbul" in the science of al-jarh wa al-ta'dil?

The Shaykh : As for the word "maqbul" in al-Taqrib by al-Hafiz Ibn Hajar... first, it is in his book, and second, it is a strange technical term, because the meaning of "maqbul" is "not maqbul." Have you seen such a technical term? The meaning of "maqbul" is "not maqbul." The problem lies in his explanation, in his definition of "maqbul." He said, "If the narrator... the hadith is something... and no one has spoken about him... then if I say about such a person that he is maqbul upon the condition of mutaba'ah, this condition makes him not maqbul in the absence of mutaba'ah. And what we observe in practice is that we find many narrators who narrate certain hadiths, and among them are those whom al-Hafiz Ibn Hajar called not maqbul. So we search and search and search, and we do not find a shahid or a mutaba' for the hadith. At that point, we say... al-Hafiz Ibn Hajar [said he is] maqbul, meaning he is not maqbul, because he has no mutaba'. ... in that ... and they are maqbul according to al-Hafiz Ibn Hajar, meaning they are not maqbul. La ilaha illa Allah.