The word "mentalis" refers to a muscle in the human body that forms the chin. While there are no direct synonyms for this word, there are some related words that can be used to describe this muscle. One term that may be used is "chin muscle." Another term that can be used to describe this muscle is "mandibular labial muscle." This muscle is located on the lower jaw and helps to control the movements of the lips and chin. Other related terms include "jaw muscle" and "facial muscle," which are both used to describe muscles in the face that control movements such as chewing and expressing emotions.