The phrase "be girt" may not be a commonly used term in modern English, but it is one that can be replaced with several synonyms. Some possible options include "be encircled," "be surrounded," "be bounded," or "be hemmed in." Each of these phrases conveys the same meaning as "be girt" - to be surrounded or enclosed by something. Depending on the context in which the phrase is used, one of these synonyms may be more appropriate than another. Ultimately, it is important to choose a synonym that fits the tone of the sentence and accurately conveys the intended meaning.