Which term describes someone or something that is the perfect example of a quality or type?

The term that best describes someone or something that exemplifies a quality or type is "epitome." It refers to a person or thing that is a perfect representation or embodiment of a particular quality or concept. For instance, you might say that a particular athlete is the epitome of sportsmanship, highlighting how they fully represent the ideals of fair play and respect.

The other options do not convey this meaning. "Surmise" refers to forming an opinion based on incomplete evidence; it does not relate to exemplifying qualities. "Interloper" describes someone who interferes or intrudes, often without invitation or right, which is unrelated to the concept of embodiment. "Bombastic" refers to speech or writing that is pompous and overly inflated, lacking in substance; thus, it does not pertain to a perfect example of a quality.