The word "beautest" is an archaic form of the superlative degree of "beautiful". While it is no longer widely used in modern English, there are several synonyms that can be used instead. These include "most beautiful", "prettiest", "gorgeous", "stunning", "radiant", "lovely", "charming", "appealing", and "attractive". Each of these synonyms conveys the same idea as "beautest" - that something is incredibly beautiful or aesthetically pleasing to the eye. Using one of these synonyms instead of the archaic "beautest" can help ensure that your language is up-to-date and easily understood by modern audiences.