“起浑名”可以翻译为“give someone a nickname” 或者 “dub someone with a derogatory/playful nickname”(若强调浑名可能含贬义或戏谑意味时),更通俗直接的表达也可以是“come up with a nickname for someone” 。
例句:
He always gives his friends funny nicknames.(他总是给他的朋友们起有趣的浑名 。)
They dubbed him "Slowpoke" because he was always the last one to finish tasks.(他们给他起了个“慢吞吞”的浑名,因为他做事总是最后一个完成 。)