Settle down is a phrasal verb that means to become calmer, more composed, and less restless. It can also mean to establish oneself permanently in one place. When replacing the phrasal verb, you can use different synonyms to convey the same or similar meanings. Some synonyms for "settle down" include "compose oneself," "calm down," "relax," "decompress," "establish roots," "make a home," "get comfortable," "set up shop," and "lay down roots." Each of these synonyms conveys the idea of finding comfort, stability, and permanency in a place, emotion, or action. Choosing the right synonym can help you to clarify your thoughts and express yourself more precisely in your writing and speaking.