The humor or irony of a single word statement such as "LEGEND" can depend greatly on its context and the expectations surrounding it. Humor, in its most fundamental essence, often hinges on a violation of expectations, typically in a manner that is harmless or innocuous. Irony, on the other hand, is a form of expression that is understood to mean something that is the opposite of its literal meaning, or a circumstance in which something that was hoped for occurs in a radically contrary manner.
Let's consider a context. Imagine the word "LEGEND" is placed beneath a picture of a completely average-looking individual doing absolutely nothing noteworthy. The humor in this case comes from the juxtaposition of the title, which implies grandness or a significant accomplishment, against the individual, who seems to be the epitome of the ordinary. Essentially, the humor resides in the unexpected discrepancy between the label and the image it is supposedly describing.
Irony could also play out in this setting. For example, if the person tagged "LEGEND" is known to be consistently unsuccessful or clumsy, people who know them would find it ironic to see them labeled as a legend. The disparity between the reality and the label would create ironic humor.
Moreover, this ironic situation becomes more humorous if the person tagged "LEGEND" has a reputation for boasting about their minimal achievements. The label would then be mockingly celebrating their mediocrity concealed as self-perceived excellence. This utility of humor as a means of subtle commentary can be a powerful tool in social situations.
Moreover, the humor in "LEGEND" could also be viewed from a linguistic perspective. As a single word sentence, it is incomplete - missing a subject, verb, or object. However, it implies that the subject is so legendary that it goes beyond the need for other words. In this manner, the simplification and exaggeration is what makes it funny.
In conclusion, the humor or irony in a single-worded sentence such as "LEGEND" greatly depends on the context, expectations, and shared understanding among the subjects. It banks on the incongruity theory, wherein the humor lies in presenting something that is contradictory to the audience's expectations. LEGEND