The phrase "are authority" can have multiple synonyms that depend on the context it is used in. Some of the synonyms for this phrase could include "have control," "possess power," "lead," "govern," "rule," "take charge," "command," or "dominate." These synonyms signify that an individual or group is in a position of influence or responsibility over a certain domain or area. It is essential to use these synonyms appropriately to convey the intended meaning and create clarity in communication. So, by using these synonyms in place of "are authority", one can bring more nuance and precision to the message they wish to communicate.