There are a few different synonyms for the word "unseeablest" that can be used to describe objects or entities that cannot be seen. Some of these synonyms include "invisible," which refers to something that cannot be seen with the naked eye, "undetectable," which implies that something cannot be observed or detected in any way, and "hidden," which describes something that is deliberately concealed or obscured from view. Other possible synonyms for "unseeablest" might include "unobservable," "unperceivable," or "imperceptible," as well as more idiosyncratic phrases like "unseeable to the naked eye" or "invisible to the senses." Ultimately, the choice of synonym will depend on the specific context in which the term is being used, as well as the writer's intended connotations and tone.