It is narrated from Sayyiduna Samurah (may Allah be pleased with him) that the Noble Prophet (peace and blessings be upon him) forbade us from giving our slaves these four names: "Aflah, Nafi', Rabah, and Najah."
Hadith Referenceسنن دارمي / من كتاب الاستئذان / 2731
(Commentary on Hadith 2730) The meanings of «أفلح» and «نجاح» are "success," and the meanings of «نافع» and «رباح» are "beneficial." Although these meanings are good, there is an aspect of pessimism that emerges from them; perhaps this is why dislike (karahah) has been expressed. For example, if someone asks: "Is there Rabaḥ or Najāḥ here?" and the answer is given, "No, there isn't," then pessimism could be inferred from this. (And Allah knows best).