Primary interest refers to a person's main focus or priority - the thing they are most concerned about. Some synonyms for primary interest would include central interest, core focus, primary focus, primary concern, main priority, and key passion. It is important to understand one's primary interest in order to prioritize and achieve goals. By identifying your primary interest, you can align your actions and decisions to work towards achieving your objectives. Whether it's a career goal, personal passion or a social cause, recognizing your primary interest is a big step towards making progress and improving your life.