There are several synonyms for the word "chemical group". A common synonym is "functional group", which is a specific group of atoms within a molecule that has a characteristic chemical behavior. Another synonym is "molecular motif", which refers to a recurring pattern or structure within a molecule. "Substituent group" is another synonym, which refers to a group of atoms that can replace a hydrogen atom within a molecule. Finally, "chemical moiety" is a less common synonym, which refers to a part of a larger molecule that can be separated and still maintain its chemical identity. All of these synonyms are important for describing the structure and behavior of complex molecules in chemistry.