The phrase "powers that be" refers to those individuals who hold significant political or social authority. There are several synonyms that can be used to convey similar meanings, such as "those in charge," "the ruling class," "the establishment," "the elite," "the brass," "the higher-ups," "the authorities," or "the leaders." These synonyms suggest a group of people who hold power and influence over others, often implying an unspoken hierarchy of control. The use of these synonyms can be helpful in providing alternatives to repetition while still conveying the same message. It is important to note that the tone and context in which these synonyms are used can also affect their meaning.