The Book Concerning the Use of Correct Words
وَحَدَّثَنَا ابْنُ رَافِعٍ، حَدَّثَنَا عَبْدُ الرَّزَّاقِ، أَخْبَرَنَا مَعْمَرٌ، عَنْ هَمَّامِ بْنِ مُنَبِّهٍ، قَالَ هَذَا مَا حَدَّثَنَا أَبُو هُرَيْرَةَ، عَنْ رَسُولِ اللَّهِ صلى الله عليه وسلم . فَذَكَرَ أَحَادِيثَ مِنْهَا وَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " لاَ يَقُولَنَّ أَحَدُكُمْ لِلْعِنَبِ الْكَرْمَ . إِنَّمَا الْكَرْمُ الرَّجُلُ الْمُسْلِمُ " .Abu Huraira reported from Allah's Messenger (ﷺ) various ahadith, one of which is this that he said:None of you should use the word al-karm for 'Inab, for karm (worthy of respect) is a Muslim person
From Sahih Muslim, whose reports the scholars accept as authentic.