The word "seest" is an old English word that is no longer in common use in modern English. It is the second-person singular form of the verb "see" in the present tense, which means "you see". There are several synonyms for the word "seest" that are commonly used in today's English language, such as "observe", "perceive", "spot", "glimpse", "view", "notice", "eyeball", and "watch". These words can be used interchangeably with "seest" depending on the context and the intended meaning. When writing or communicating, be mindful of using the appropriate synonym to ensure clarity and accuracy.