Pumiceous is an adjective that describes something that has a rough and porous texture, similar to that of pumice stone. While this word is specific in its meaning, there are several synonyms that can be used to convey a similar idea. For instance, the word coarse is often used to describe something that has a rough surface texture. Porous is another word that is commonly used in place of pumiceous. The term spongy can also be used to describe a texture that is similar to that of pumice stone. Other synonyms for pumiceous include rough, gritty, and granular. These words can help to convey the meaning of pumiceous in different contexts.