The term 'LIFE OF ___' can be filled in with the answers RILEY (5 letters), PI (2 letters), and EASE (4 letters). RILEY is a common name, derived from the Old English word for 'rye clearing'. PI is a mathematical constant, approximately equal to 3.14159, which is used to calculate the area of a circle. EASE is a state of comfort or freedom from difficulty or hardship. Together, these three words form the phrase 'LIFE OF RILEY', which is an idiom meaning a life of EASE and comfort.