The color "red-grey" is a unique shade that combines the warmth of red and the steely coolness of grey. However, if you're looking to describe this color with more variety, there are several synonyms you can use. For instance, "rusty grey" is a term that describes a similar shade, emphasizing the hue's red undertones. Other options include "ashen red," "muted maroon," or "brick-toned grey" - all of which emphasize different elements of the color. Using synonyms for "red-grey" can help add depth and nuance to descriptions and create a more vivid picture for readers or listeners.