Clear coast has different synonyms that depend on the context. If you are referring to a coast that has crystal clear water, some synonyms you can use include pristine coast, transparent coast, or crystalline coast. On the other hand, if you are talking about a coast that is free from any obstructions or barriers, you may use open coast or unobstructed coast. If you want to emphasize the absence of clouds or other weather disturbances, you may use the term sunny coast or cloudless coast. Ultimately, the synonym you choose depends on the specific meaning you want to convey and the context in which you are using the term.