Red river is a term that refers to a river with red or reddish-colored waters. This coloration may be due to sediment or minerals that are naturally present in the water, or it could be a result of human pollution. There are several synonyms that can be used to describe a red river, such as rust-colored, brick-hued, or blood-red. Other options include crimson, scarlet, or burgundy, which are all variations of the color red. The use of these synonyms in descriptive writing can help to add depth and richness to the language, painting a vivid picture for the reader.