Argils are defined as a type of clay that is often used in pottery or in the making of bricks. There are several synonyms for argils that can be used interchangeably with the word, depending on the context. Clay, mud, dirt, and soil are some of the most common synonyms for argils. Other synonyms might include loam, silt, or earth, depending on the specific characteristics of the material being described. It's important to choose the appropriate synonym based on the intended meaning and the context in which the term is being used, in order to ensure clear communication and effective expression of ideas.