Iridescent is an adjective used to describe something that reflects or shines with various colors, much like an oil slick. Some synonyms for iridescent include dazzling, opalescent, prismatic, shimmering, sparkling, and colorful. Dazzling refers to something that is bright and shiny, while opalescent describes something that has a milky, pearly sheen. Prismatic suggests something that reflects different colors like a prism, while shimmering and sparkling both imply a play of light and color. Finally, colorful describes something that is full of a variety of bright colors. Each of these words is a great alternative to iridescent and can add extra depth and color to your writing.