What term describes an elderly person?

The term that best describes an elderly person is "old." This designation typically refers to individuals who have reached an advanced age, often associated with the later stages of life. In various contexts, "old" can encompass a range of ages, but it is commonly used to signify those who are retired or have significant life experience, often age 65 and older.

In contrast to the correct choice, other terms do not accurately capture the essence of being elderly. The term "young adult" pertains to individuals generally in their late teens to early twenties and focuses on a different life stage altogether. "Sprightly" suggests energy and liveliness, which may not be characteristic of all elderly individuals. Lastly, "middle-aged" refers to people typically in their 40s to 60s, who are neither young nor considered elderly. Therefore, "old" is the most fitting term to describe an elderly person.