Abu Hurairah (May Allah be pleased with him) said:
The Messenger of Allah (ﷺ) said, "None of you should use the word Al-Karm for grapes, for Al-Karm is a Muslim (worthy of respect)."[Al- Bukhari and Muslim]Another narration is: "Verily, Al-Karm is the heart of a true believer."Another narration is: "People have named grapes as Al-Karm; verily, only the heart of a believer is Al-Karm." (DE)
App reference (DE): Book 18, Hadith 230 (DE)
Arabic/English book reference (DE): Book 18, Hadith 1740 (DE)