From the given options, select the Figure of Speech (Poetic Device) used in the expression:

The gloom of despair

Metaphor

The figure of speech used in the expression "The gloom of despair" is metaphor.

A metaphor is a figure of speech in which one thing is compared to another thing without using the words "like" or "as." In this case, the abstract concept of despair is being compared to a physical thing, such as gloom. This creates a sense of the darkness and hopelessness that despair can bring.

The other answer choices are incorrect. Simile is a comparison between two things using the words "like" or "as." Pun is a play on words. Personification is a figure of speech in which inanimate objects are given human qualities. None of these devices are used in the expression "The gloom of despair.".