The term 'high interest' can be summarized by two crossword solutions: USURY (5 letters) and FASCINATION (11 letters). USURY is the practice of lending money at an unreasonably high rate of interest. It has been around since ancient times and is still practiced today, although it is illegal in many countries. FASCINATION is a strong feeling of interest or admiration for something. It is often used to describe an intense interest in a particular subject or activity.