Argillous is an adjective used to describe something composed of or resembling clay. There are several related synonyms that can be used to convey a similar meaning. For example, clayey is an adjective that refers to something having the properties of clay, while claylike describes something resembling or similar to clay. Another possible synonym is loamy, which is used to describe soil that contains a significant amount of sand, silt, and clay. Additionally, clayey, loamy, or argillaceous all refer to soil with a high proportion of clay, whereas silty clay describes a type of clay soil with a high proportion of silt. Ultimately, these synonyms can be used interchangeably to describe materials or environments that share the characteristic of being argillous.