There are many synonyms for the phrase "be relaxed" that can be used in a variety of situations. One of the most common is "chill out," which is often used in more casual settings. For a more formal tone, one might use "unwind" or "de-stress." Other options include "calm down," "mellow out," "let go," and "unwind." Each of these phrases carries a slightly different connotation, so it's important to choose the right one for the situation. Overall, using a synonym for "be relaxed" can help convey a more nuanced message and create a more effective communication.