The expression "eager as a beaver" is an example of which literary device?

The expression "eager as a beaver" is an example of a simile. A simile is a figure of speech that makes a comparison between two different things using the words "like" or "as." In this case, the eagerness of a person is compared to the industrious nature of a beaver, which is known for its hardworking and proactive behavior. This comparison helps convey the intensity of one's eagerness by linking it to a well-known characteristic of beavers, thereby enhancing the imagery and understanding of the expression.

Other literary devices mentioned—like metaphor, hyperbole, and synecdoche—serve different functions. A metaphor implies a direct comparison without using "like" or "as," hyperbole involves exaggerated statements, and synecdoche refers to using a part to represent a whole or vice versa. Therefore, the defining characteristics of a simile make it the correct choice in this context.