Zaynab's original name was Barrah. It was said that she was praising herself by such a name, so the Messenger of Allah ﷺ named her Zaynab.
حدثنا أبو بكر حدثنا غندر عن شعبة عن عطاء بن أبي ميمونة قال سمعت أبا رافع يحدث
أن زينب كان اسمها برة فقيل لها تزكي نفسها فسماها رسول الله ﷺ زينب
Bukhari reported it in the Book of Manners, Chapter on Changing a Name to a Better One, hadith 6192, from the hadith of Ghundar through this route, and Muslim in the Book of Manners, Chapter on the Desirability of Changing an Ugly Name to a Good One, etc., hadith 2141, from Abu Bakr bin Abu Shayba through this route.