In the sentence, "The folly of youth stands in stark contrast to the wisdom of age," the word "folly" is the word part you are asking about. The word part "folly" is a noun and it represents a lack of good sense or foolishness. To identify the word part in a sentence, you can simply look for the word that carries the intended meaning and serves as a distinct part of speech, such as a noun, verb, adjective, or adverb. In this case, "folly" is a noun that represents a concept or idea.
