The phrase "with authority" refers to having an official or commanding power. There are several synonyms for this term, including "authoritative," "commanding," "dominant," "imperative," "official," and "powerful." Similar phrases include "with power," "with control," and "with influence." Using synonyms for "with authority" can add variety and emphasis to your writing. For example, instead of saying "He spoke with authority," you could say "He spoke authoritatively," or "His commanding voice demanded attention." Overall, knowing different synonyms can help you communicate meaning effectively while avoiding repetition.