Monomorphous means having a single form or appearance, but there are several synonyms you can use to vary your writing. These include uniform, unvaried, invariant, homogenous, and unchanging. Other words that can be used as synonyms for monomorphous include consistent, identical, constant, regular, and even. This word can be utilized in various contexts, such as in biology, where it refers to a species having a single morphologic form, or in fashion, where it can describe a single style or trend. Regardless of the context, using synonyms can help you mix up your writing and keep it interesting.