The term 'preoccupy the mind of' can be summarized by the word 'OBSESS, ' which is a 6-letter word. Obsessing is an intense focus on something that can cause a person to become preoccupied with it, often to the point of distraction from other activities. It can be a symptom of mental health issues such as anxiety and depression, or it can be a normal part of life when a person is passionate about something.