There are various synonyms available for the term "metallic brown". Some of the common terms that you can use instead of "metallic brown" are bronze, coppery-brown, auburn, mahogany, burnt sienna, rust, deep brown, and chocolate. The term "bronze" is generally used to describe a dark metal-like brown color, often with gold and copper highlights. Similarly, a "coppery-brown" color is often associated with metallic qualities and a shiny luster. Meanwhile, "mahogany" represents a darker brown color with a red hue and is often used in furniture and woodworking. "Burnt sienna" and "rust" are shades of brown with orange and red hues, while "deep brown" and "chocolate" are rich, dark brown colors. All of these synonyms can be used interchangeably with "metallic brown" depending on the context and usage.