Some synonyms for the phrase "become tranquil" include "calm down," "compose oneself," "relax," "settle down," and "unwind." These terms carry a sense of releasing tension or agitation and finding inner peace or stillness. Other possible synonyms might include "center oneself," "quiet the mind," "find serenity," or "attain inner balance." The concept of becoming tranquil is often associated with mindfulness practices, meditation, or other relaxation techniques. Whether achieved through focused breathing, physical movement, or mental exercises, the goal is to soothe the mind and body and restore a sense of calm and well-being.