Laminous is an uncommon word that means shiny or luminous, specifically in reference to flat surfaces. Some synonyms that could be used in place of laminous include glossy, gleaming, radiant, sparkling, and polished. Other related words to consider might include luminous, lustrous, sheeny, iridescent, and shiny. Depending on the context of the sentence, relevant synonyms might also include resplendent, incandescent, or effulgent. In general, when looking for other ways to describe a surface that reflects light, it can be helpful to consider not just visual appearance, but also texture and other sensory qualities that might be relevant.