What is a fanciful expression that often uses an extended metaphor or surprising analogy?

A fanciful expression characterized by the use of an extended metaphor or a surprising analogy is known as a conceit. This literary device often involves an elaborate comparison between two seemingly dissimilar things, allowing for a deeper exploration of their relationships and meanings. By drawing connections between these disparate elements, a conceit can provoke thought and highlight underlying themes in a way that more straightforward comparisons might not achieve. For instance, a poet might compare the complexities of love to the intricacies of a mathematical equation, showcasing both the beauty and confusion involved in each.

This contrasts with similes, which make direct comparisons using "like" or "as," and are generally simpler and more straightforward. Irony refers to a situation where there is a contradiction between appearance and reality, often highlighting the gap between expectations and outcomes. Pathos is an emotional appeal meant to evoke feelings in the audience, rather than making creative comparisons. Thus, considering these definitions, the choice of conceit as a fanciful expression stands out for its complexity and depth in crafting connections through metaphor.