The word "behoves" is a less commonly used word in modern English, however there are several synonyms that can be used in its place. These synonyms include "behooves", "is necessary", "is incumbent upon", "is required", "is essential", "is vital", "is imperative", "is mandatory", "is obligatory" and "is compulsory". All of these synonyms suggest that something is required or expected of someone or something, and cannot be avoided or neglected. These words are often used in formal language, and have a sense of responsibility or duty associated with them. It is important to choose the right synonym depending on the context and tone of the sentence.