"五彩缤纷" in Engpsh is "vibrant colors".
It comes from the Chinese expression "五彩斑斓" which pterally means "five-colored and speckled". This expression is used to describe something that is brightly colored and visually attractive.
Here are some example sentences in Engpsh with their translations:
The tropical fish has vibrant colors that are truly captivating. (热带鱼有五彩缤纷的色彩，简直令人着迷。)
The street performers were dressed in vibrant colors, making them stand out from the crowd. (街头表演者穿着五彩缤纷的服装，使他们从人群中脱颖而出。)
The sunset was a beautiful display of vibrant colors. (日落是五彩缤纷的美丽景象。)