The term COSTLY DARK BROWN FUR can be summarized as SABLE, a five-letter word. SABLE is a species of marten, a small carnivorous mammal native to cold regions of the Northern Hemisphere. The fur of the SABLE is highly valued and is used in the production of luxury clothing and accessories. It is dark brown in color and has a glossy sheen. The fur is also very expensive, making it a symbol of wealth and status.